# The Information Schema

The information schema consists of a set of views that contain information about the objects defined in the current database. The information schema is defined in the SQL standard and can therefore be expected to be portable and remain stable — unlike the system catalogs, which are specific to PostgreSQL and are modeled after implementation concerns. The information schema views do not, however, contain information about PostgreSQL-specific features; to inquire about those you need to query the system catalogs or other PostgreSQL-specific views.

When querying the database for constraint information, it is possible for a standard-compliant query that expects to return one row to return several. This is because the SQL standard requires constraint names to be unique within a schema, but PostgreSQL does not enforce this restriction. PostgreSQL automatically-generated constraint names avoid duplicates in the same schema, but users can specify such duplicate names.

This problem can appear when querying information schema views such as `check_constraint_routine_usage`, `check_constraints`, `domain_constraints`, and `referential_constraints`. Some other views have similar issues but contain the table name to help distinguish duplicate rows, e.g., `constraint_column_usage`, `constraint_table_usage`, `table_constraints`.

## The Schema

The information schema itself is a schema named `information_schema`. This schema automatically exists in all databases. The owner of this schema is the initial database user in the cluster, and that user naturally has all the privileges on this schema, including the ability to drop it (but the space savings achieved by that are minuscule).

By default, the information schema is not in the schema search path, so you need to access all objects in it through qualified names. Since the names of some of the objects in the information schema are generic names that might occur in user applications, you should be careful if you want to put the information schema in the path.

## Data Types

The columns of the information schema views use special data types that are defined in the information schema. These are defined as simple domains over ordinary built-in types. You should not use these types for work outside the information schema, but your applications must be prepared for them if they select from the information schema.

These types are:

`cardinal_number`

- A nonnegative integer.

`character_data`

- A character string (without specific maximum length).

`sql_identifier`

- A character string. This type is used for SQL identifiers, the type `character_data` is used for any other kind of text data.

`time_stamp`

- A domain over the type `timestamp with time zone`

`yes_or_no`

- A character string domain that contains either `YES` or `NO`. This is used to represent Boolean (true/false) data in the information schema. (The information schema was invented before the type `boolean` was added to the SQL standard, so this convention is necessary to keep the information schema backward compatible.)

Every column in the information schema has one of these five types.

## `information_schema_catalog_name`

`information_schema_catalog_name` is a table that always contains one row and one column containing the name of the current database (current catalog, in SQL terminology).

## information_schema_catalog_name Columns

Column Type Description
catalog_name `sql_identifier` Name of the database that contains this information schema

## `administrable_role_&zwsp;authorizations`

The view `administrable_role_authorizations` identifies all roles that the current user has the admin option for.

## administrable_role_authorizations Columns

Column Type Description
grantee `sql_identifier` Name of the role to which this role membership was granted (can be the current user, or a different role in case of nested role memberships)
role_name `sql_identifier` Name of a role
is_grantable `yes_or_no` Always `YES`

## `applicable_roles`

The view `applicable_roles` identifies all roles whose privileges the current user can use. This means there is some chain of role grants from the current user to the role in question. The current user itself is also an applicable role. The set of applicable roles is generally used for permission checking.

## applicable_roles Columns

Column Type Description
grantee `sql_identifier` Name of the role to which this role membership was granted (can be the current user, or a different role in case of nested role memberships)
role_name `sql_identifier` Name of a role
is_grantable `yes_or_no` `YES` if the grantee has the admin option on the role, `NO` if not

## `attributes`

The view `attributes` contains information about the attributes of composite data types defined in the database. (Note that the view does not give information about table columns, which are sometimes called attributes in PostgreSQL contexts.) Only those attributes are shown that the current user has access to (by way of being the owner of or having some privilege on the type).

## attributes Columns

Column Type Description
udt_catalog `sql_identifier` Name of the database containing the data type (always the current database)
udt_schema `sql_identifier` Name of the schema containing the data type
udt_name `sql_identifier` Name of the data type
attribute_name `sql_identifier` Name of the attribute
ordinal_position `cardinal_number` Ordinal position of the attribute within the data type (count starts at 1)
attribute_default `character_data` Default expression of the attribute
is_nullable `yes_or_no` `YES` if the attribute is possibly nullable, `NO` if it is known not nullable.
data_type `character_data` Data type of the attribute, if it is a built-in type, or `ARRAY` if it is some array (in that case, see the view `element_types`), else `USER-DEFINED` (in that case, the type is identified in `attribute_udt_name` and associated columns).
character_maximum_length `cardinal_number` If `data_type` identifies a character or bit string type, the declared maximum length; null for all other data types or if no maximum length was declared.
character_octet_length `cardinal_number` If `data_type` identifies a character type, the maximum possible length in octets (bytes) of a datum; null for all other data types. The maximum octet length depends on the declared character maximum length (see above) and the server encoding.
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Name of the database containing the collation of the attribute (always the current database), null if default or the data type of the attribute is not collatable
collation_schema `sql_identifier` Name of the schema containing the collation of the attribute, null if default or the data type of the attribute is not collatable
collation_name `sql_identifier` Name of the collation of the attribute, null if default or the data type of the attribute is not collatable
numeric_precision `cardinal_number` If `data_type` identifies a numeric type, this column contains the (declared or implicit) precision of the type for this attribute. The precision indicates the number of significant digits. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`. For all other data types, this column is null.
numeric_precision_radix `cardinal_number` If `data_type` identifies a numeric type, this column indicates in which base the values in the columns `numeric_precision` and `numeric_scale` are expressed. The value is either 2 or 10. For all other data types, this column is null.
numeric_scale `cardinal_number` If `data_type` identifies an exact numeric type, this column contains the (declared or implicit) scale of the type for this attribute. The scale indicates the number of significant digits to the right of the decimal point. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`. For all other data types, this column is null.
datetime_precision `cardinal_number` If `data_type` identifies a date, time, timestamp, or interval type, this column contains the (declared or implicit) fractional seconds precision of the type for this attribute, that is, the number of decimal digits maintained following the decimal point in the seconds value. For all other data types, this column is null.
interval_type `character_data` If `data_type` identifies an interval type, this column contains the specification which fields the intervals include for this attribute, e.g., `YEAR TO MONTH`, `DAY TO SECOND`, etc. If no field restrictions were specified (that is, the interval accepts all fields), and for all other data types, this field is null.
interval_precision `cardinal_number` Applies to a feature not available in PostgreSQL (see `datetime_precision` for the fractional seconds precision of interval type attributes)
attribute_udt_catalog `sql_identifier` Name of the database that the attribute data type is defined in (always the current database)
attribute_udt_schema `sql_identifier` Name of the schema that the attribute data type is defined in
attribute_udt_name `sql_identifier` Name of the attribute data type
scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
maximum_cardinality `cardinal_number` Always null, because arrays always have unlimited maximum cardinality in PostgreSQL
dtd_identifier `sql_identifier` An identifier of the data type descriptor of the attribute, unique among the data type descriptors pertaining to the composite type. This is mainly useful for joining with other instances of such identifiers. (The specific format of the identifier is not defined and not guaranteed to remain the same in future versions.)
is_derived_reference_attribute `yes_or_no` Applies to a feature not available in PostgreSQL

See also under infoschema-columns, a similarly structured view, for further information on some of the columns.

## `character_sets`

The view `character_sets` identifies the character sets available in the current database. Since PostgreSQL does not support multiple character sets within one database, this view only shows one, which is the database encoding.

Take note of how the following terms are used in the SQL standard:

character repertoire

- An abstract collection of characters, for example `UNICODE`, `UCS`, or `LATIN1`. Not exposed as an SQL object, but visible in this view.

character encoding form

- An encoding of some character repertoire. Most older character repertoires only use one encoding form, and so there are no separate names for them (e.g., `LATIN2` is an encoding form applicable to the `LATIN2` repertoire). But for example Unicode has the encoding forms `UTF8`, `UTF16`, etc. (not all supported by PostgreSQL). Encoding forms are not exposed as an SQL object, but are visible in this view.

character set

- A named SQL object that identifies a character repertoire, a character encoding, and a default collation. A predefined character set would typically have the same name as an encoding form, but users could define other names. For example, the character set `UTF8` would typically identify the character repertoire `UCS`, encoding form `UTF8`, and some default collation.

You can think of an encoding in PostgreSQL either as a character set or a character encoding form. They will have the same name, and there can only be one in one database.

## character_sets Columns

Column Type Description
character_set_catalog `sql_identifier` Character sets are currently not implemented as schema objects, so this column is null.
character_set_schema `sql_identifier` Character sets are currently not implemented as schema objects, so this column is null.
character_set_name `sql_identifier` Name of the character set, currently implemented as showing the name of the database encoding
character_repertoire `sql_identifier` Character repertoire, showing `UCS` if the encoding is `UTF8`, else just the encoding name
form_of_use `sql_identifier` Character encoding form, same as the database encoding
default_collate_catalog `sql_identifier` Name of the database containing the default collation (always the current database, if any collation is identified)
default_collate_schema `sql_identifier` Name of the schema containing the default collation
default_collate_name `sql_identifier` Name of the default collation. The default collation is identified as the collation that matches the `COLLATE` and `CTYPE` settings of the current database. If there is no such collation, then this column and the associated schema and catalog columns are null.

## `check_constraint_routine_usage`

The view `check_constraint_routine_usage` identifies routines (functions and procedures) that are used by a check constraint. Only those routines are shown that are owned by a currently enabled role.

## check_constraint_routine_usage Columns

Column Type Description
constraint_catalog `sql_identifier` Name of the database containing the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema containing the constraint
constraint_name `sql_identifier` Name of the constraint
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.

## `check_constraints`

The view `check_constraints` contains all check constraints, either defined on a table or on a domain, that are owned by a currently enabled role. (The owner of the table or domain is the owner of the constraint.)

The SQL standard considers not-null constraints to be check constraints with a `CHECK (`column_name` IS NOT NULL)` expression. So not-null constraints are also included here and don't have a separate view.

## check_constraints Columns

Column Type Description
constraint_catalog `sql_identifier` Name of the database containing the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema containing the constraint
constraint_name `sql_identifier` Name of the constraint
check_clause `character_data` The check expression of the check constraint

## `collations`

The view `collations` contains the collations available in the current database.

## collations Columns

Column Type Description
collation_catalog `sql_identifier` Name of the database containing the collation (always the current database)
collation_schema `sql_identifier` Name of the schema containing the collation
collation_name `sql_identifier` Name of the default collation
pad_attribute `character_data` Always `NO PAD` (The alternative `PAD SPACE` is not supported by PostgreSQL.)

## `collation_character_set_&zwsp;applicability`

The view `collation_character_set_applicability` identifies which character set the available collations are applicable to. In PostgreSQL, there is only one character set per database (see explanation in infoschema-character-sets), so this view does not provide much useful information.

## collation_character_set_applicability Columns

Column Type Description
collation_catalog `sql_identifier` Name of the database containing the collation (always the current database)
collation_schema `sql_identifier` Name of the schema containing the collation
collation_name `sql_identifier` Name of the default collation
character_set_catalog `sql_identifier` Character sets are currently not implemented as schema objects, so this column is null
character_set_schema `sql_identifier` Character sets are currently not implemented as schema objects, so this column is null
character_set_name `sql_identifier` Name of the character set

## `column_column_usage`

The view `column_column_usage` identifies all generated columns that depend on another base column in the same table. Only tables owned by a currently enabled role are included.

## column_column_usage Columns

Column Type Description
table_catalog `sql_identifier` Name of the database containing the table (always the current database)
table_schema `sql_identifier` Name of the schema containing the table
table_name `sql_identifier` Name of the table
column_name `sql_identifier` Name of the base column that a generated column depends on
dependent_column `sql_identifier` Name of the generated column

## `column_domain_usage`

The view `column_domain_usage` identifies all columns (of a table or a view) that make use of some domain defined in the current database and owned by a currently enabled role.

## column_domain_usage Columns

Column Type Description
domain_catalog `sql_identifier` Name of the database containing the domain (always the current database)
domain_schema `sql_identifier` Name of the schema containing the domain
domain_name `sql_identifier` Name of the domain
table_catalog `sql_identifier` Name of the database containing the table (always the current database)
table_schema `sql_identifier` Name of the schema containing the table
table_name `sql_identifier` Name of the table
column_name `sql_identifier` Name of the column

## `column_options`

The view `column_options` contains all the options defined for foreign table columns in the current database. Only those foreign table columns are shown that the current user has access to (by way of being the owner or having some privilege).

## column_options Columns

Column Type Description
table_catalog `sql_identifier` Name of the database that contains the foreign table (always the current database)
table_schema `sql_identifier` Name of the schema that contains the foreign table
table_name `sql_identifier` Name of the foreign table
column_name `sql_identifier` Name of the column
option_name `sql_identifier` Name of an option
option_value `character_data` Value of the option

## `column_privileges`

The view `column_privileges` identifies all privileges granted on columns to a currently enabled role or by a currently enabled role. There is one row for each combination of column, grantor, and grantee.

If a privilege has been granted on an entire table, it will show up in this view as a grant for each column, but only for the privilege types where column granularity is possible: `SELECT`, `INSERT`, `UPDATE`, `REFERENCES`.

## column_privileges Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
table_catalog `sql_identifier` Name of the database that contains the table that contains the column (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that contains the column
table_name `sql_identifier` Name of the table that contains the column
column_name `sql_identifier` Name of the column
privilege_type `character_data` Type of the privilege: `SELECT`, `INSERT`, `UPDATE`, or `REFERENCES`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `column_udt_usage`

The view `column_udt_usage` identifies all columns that use data types owned by a currently enabled role. Note that in PostgreSQL, built-in data types behave like user-defined types, so they are included here as well. See also infoschema-columns for details.

## column_udt_usage Columns

Column Type Description
udt_catalog `sql_identifier` Name of the database that the column data type (the underlying type of the domain, if applicable) is defined in (always the current database)
udt_schema `sql_identifier` Name of the schema that the column data type (the underlying type of the domain, if applicable) is defined in
udt_name `sql_identifier` Name of the column data type (the underlying type of the domain, if applicable)
table_catalog `sql_identifier` Name of the database containing the table (always the current database)
table_schema `sql_identifier` Name of the schema containing the table
table_name `sql_identifier` Name of the table
column_name `sql_identifier` Name of the column

## `columns`

The view `columns` contains information about all table columns (or view columns) in the database. System columns (`ctid`, etc.) are not included. Only those columns are shown that the current user has access to (by way of being the owner or having some privilege).

## columns Columns

Column Type Description
table_catalog `sql_identifier` Name of the database containing the table (always the current database)
table_schema `sql_identifier` Name of the schema containing the table
table_name `sql_identifier` Name of the table
column_name `sql_identifier` Name of the column
ordinal_position `cardinal_number` Ordinal position of the column within the table (count starts at 1)
column_default `character_data` Default expression of the column
is_nullable `yes_or_no` `YES` if the column is possibly nullable, `NO` if it is known not nullable. A not-null constraint is one way a column can be known not nullable, but there can be others.
data_type `character_data` Data type of the column, if it is a built-in type, or `ARRAY` if it is some array (in that case, see the view `element_types`), else `USER-DEFINED` (in that case, the type is identified in `udt_name` and associated columns). If the column is based on a domain, this column refers to the type underlying the domain (and the domain is identified in `domain_name` and associated columns).
character_maximum_length `cardinal_number` If `data_type` identifies a character or bit string type, the declared maximum length; null for all other data types or if no maximum length was declared.
character_octet_length `cardinal_number` If `data_type` identifies a character type, the maximum possible length in octets (bytes) of a datum; null for all other data types. The maximum octet length depends on the declared character maximum length (see above) and the server encoding.
numeric_precision `cardinal_number` If `data_type` identifies a numeric type, this column contains the (declared or implicit) precision of the type for this column. The precision indicates the number of significant digits. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`. For all other data types, this column is null.
numeric_precision_radix `cardinal_number` If `data_type` identifies a numeric type, this column indicates in which base the values in the columns `numeric_precision` and `numeric_scale` are expressed. The value is either 2 or 10. For all other data types, this column is null.
numeric_scale `cardinal_number` If `data_type` identifies an exact numeric type, this column contains the (declared or implicit) scale of the type for this column. The scale indicates the number of significant digits to the right of the decimal point. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`. For all other data types, this column is null.
datetime_precision `cardinal_number` If `data_type` identifies a date, time, timestamp, or interval type, this column contains the (declared or implicit) fractional seconds precision of the type for this column, that is, the number of decimal digits maintained following the decimal point in the seconds value. For all other data types, this column is null.
interval_type `character_data` If `data_type` identifies an interval type, this column contains the specification which fields the intervals include for this column, e.g., `YEAR TO MONTH`, `DAY TO SECOND`, etc. If no field restrictions were specified (that is, the interval accepts all fields), and for all other data types, this field is null.
interval_precision `cardinal_number` Applies to a feature not available in PostgreSQL (see `datetime_precision` for the fractional seconds precision of interval type columns)
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Name of the database containing the collation of the column (always the current database), null if default or the data type of the column is not collatable
collation_schema `sql_identifier` Name of the schema containing the collation of the column, null if default or the data type of the column is not collatable
collation_name `sql_identifier` Name of the collation of the column, null if default or the data type of the column is not collatable
domain_catalog `sql_identifier` If the column has a domain type, the name of the database that the domain is defined in (always the current database), else null.
domain_schema `sql_identifier` If the column has a domain type, the name of the schema that the domain is defined in, else null.
domain_name `sql_identifier` If the column has a domain type, the name of the domain, else null.
udt_catalog `sql_identifier` Name of the database that the column data type (the underlying type of the domain, if applicable) is defined in (always the current database)
udt_schema `sql_identifier` Name of the schema that the column data type (the underlying type of the domain, if applicable) is defined in
udt_name `sql_identifier` Name of the column data type (the underlying type of the domain, if applicable)
scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
maximum_cardinality `cardinal_number` Always null, because arrays always have unlimited maximum cardinality in PostgreSQL
dtd_identifier `sql_identifier` An identifier of the data type descriptor of the column, unique among the data type descriptors pertaining to the table. This is mainly useful for joining with other instances of such identifiers. (The specific format of the identifier is not defined and not guaranteed to remain the same in future versions.)
is_self_referencing `yes_or_no` Applies to a feature not available in PostgreSQL
is_identity `yes_or_no` If the column is an identity column, then `YES`, else `NO`.
identity_generation `character_data` If the column is an identity column, then `ALWAYS` or `BY DEFAULT`, reflecting the definition of the column.
identity_start `character_data` If the column is an identity column, then the start value of the internal sequence, else null.
identity_increment `character_data` If the column is an identity column, then the increment of the internal sequence, else null.
identity_maximum `character_data` If the column is an identity column, then the maximum value of the internal sequence, else null.
identity_minimum `character_data` If the column is an identity column, then the minimum value of the internal sequence, else null.
identity_cycle `yes_or_no` If the column is an identity column, then `YES` if the internal sequence cycles or `NO` if it does not; otherwise null.
is_generated `character_data` If the column is a generated column, then `ALWAYS`, else `NEVER`.
generation_expression `character_data` If the column is a generated column, then the generation expression, else null.
is_updatable `yes_or_no` `YES` if the column is updatable, `NO` if not (Columns in base tables are always updatable, columns in views not necessarily)

Since data types can be defined in a variety of ways in SQL, and PostgreSQL contains additional ways to define data types, their representation in the information schema can be somewhat difficult. The column `data_type` is supposed to identify the underlying built-in type of the column. In PostgreSQL, this means that the type is defined in the system catalog schema `pg_catalog`. This column might be useful if the application can handle the well-known built-in types specially (for example, format the numeric types differently or use the data in the precision columns). The columns `udt_name`, `udt_schema`, and `udt_catalog` always identify the underlying data type of the column, even if the column is based on a domain. (Since PostgreSQL treats built-in types like user-defined types, built-in types appear here as well. This is an extension of the SQL standard.) These columns should be used if an application wants to process data differently according to the type, because in that case it wouldn't matter if the column is really based on a domain. If the column is based on a domain, the identity of the domain is stored in the columns `domain_name`, `domain_schema`, and `domain_catalog`. If you want to pair up columns with their associated data types and treat domains as separate types, you could write `coalesce(domain_name, udt_name)`, etc.

## `constraint_column_usage`

The view `constraint_column_usage` identifies all columns in the current database that are used by some constraint. Only those columns are shown that are contained in a table owned by a currently enabled role. For a check constraint, this view identifies the columns that are used in the check expression. For a not-null constraint, this view identifies the column that the constraint is defined on. For a foreign key constraint, this view identifies the columns that the foreign key references. For a unique or primary key constraint, this view identifies the constrained columns.

## constraint_column_usage Columns

Column Type Description
table_catalog `sql_identifier` Name of the database that contains the table that contains the column that is used by some constraint (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that contains the column that is used by some constraint
table_name `sql_identifier` Name of the table that contains the column that is used by some constraint
column_name `sql_identifier` Name of the column that is used by some constraint
constraint_catalog `sql_identifier` Name of the database that contains the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema that contains the constraint
constraint_name `sql_identifier` Name of the constraint

## `constraint_table_usage`

The view `constraint_table_usage` identifies all tables in the current database that are used by some constraint and are owned by a currently enabled role. (This is different from the view `table_constraints`, which identifies all table constraints along with the table they are defined on.) For a foreign key constraint, this view identifies the table that the foreign key references. For a unique or primary key constraint, this view simply identifies the table the constraint belongs to. Check constraints and not-null constraints are not included in this view.

## constraint_table_usage Columns

Column Type Description
table_catalog `sql_identifier` Name of the database that contains the table that is used by some constraint (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that is used by some constraint
table_name `sql_identifier` Name of the table that is used by some constraint
constraint_catalog `sql_identifier` Name of the database that contains the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema that contains the constraint
constraint_name `sql_identifier` Name of the constraint

## `data_type_privileges`

The view `data_type_privileges` identifies all data type descriptors that the current user has access to, by way of being the owner of the described object or having some privilege for it. A data type descriptor is generated whenever a data type is used in the definition of a table column, a domain, or a function (as parameter or return type) and stores some information about how the data type is used in that instance (for example, the declared maximum length, if applicable). Each data type descriptor is assigned an arbitrary identifier that is unique among the data type descriptor identifiers assigned for one object (table, domain, function). This view is probably not useful for applications, but it is used to define some other views in the information schema.

## data_type_privileges Columns

Column Type Description
object_catalog `sql_identifier` Name of the database that contains the described object (always the current database)
object_schema `sql_identifier` Name of the schema that contains the described object
object_name `sql_identifier` Name of the described object
object_type `character_data` The type of the described object: one of `TABLE` (the data type descriptor pertains to a column of that table), `DOMAIN` (the data type descriptors pertains to that domain), `ROUTINE` (the data type descriptor pertains to a parameter or the return data type of that function).
dtd_identifier `sql_identifier` The identifier of the data type descriptor, which is unique among the data type descriptors for that same object.

## `domain_constraints`

The view `domain_constraints` contains all constraints belonging to domains defined in the current database. Only those domains are shown that the current user has access to (by way of being the owner or having some privilege).

## domain_constraints Columns

Column Type Description
constraint_catalog `sql_identifier` Name of the database that contains the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema that contains the constraint
constraint_name `sql_identifier` Name of the constraint
domain_catalog `sql_identifier` Name of the database that contains the domain (always the current database)
domain_schema `sql_identifier` Name of the schema that contains the domain
domain_name `sql_identifier` Name of the domain
is_deferrable `yes_or_no` `YES` if the constraint is deferrable, `NO` if not
initially_deferred `yes_or_no` `YES` if the constraint is deferrable and initially deferred, `NO` if not

## `domain_udt_usage`

The view `domain_udt_usage` identifies all domains that are based on data types owned by a currently enabled role. Note that in PostgreSQL, built-in data types behave like user-defined types, so they are included here as well.

## domain_udt_usage Columns

Column Type Description
udt_catalog `sql_identifier` Name of the database that the domain data type is defined in (always the current database)
udt_schema `sql_identifier` Name of the schema that the domain data type is defined in
udt_name `sql_identifier` Name of the domain data type
domain_catalog `sql_identifier` Name of the database that contains the domain (always the current database)
domain_schema `sql_identifier` Name of the schema that contains the domain
domain_name `sql_identifier` Name of the domain

## `domains`

The view `domains` contains all domains defined in the current database. Only those domains are shown that the current user has access to (by way of being the owner or having some privilege).

## domains Columns

Column Type Description
domain_catalog `sql_identifier` Name of the database that contains the domain (always the current database)
domain_schema `sql_identifier` Name of the schema that contains the domain
domain_name `sql_identifier` Name of the domain
data_type `character_data` Data type of the domain, if it is a built-in type, or `ARRAY` if it is some array (in that case, see the view `element_types`), else `USER-DEFINED` (in that case, the type is identified in `udt_name` and associated columns).
character_maximum_length `cardinal_number` If the domain has a character or bit string type, the declared maximum length; null for all other data types or if no maximum length was declared.
character_octet_length `cardinal_number` If the domain has a character type, the maximum possible length in octets (bytes) of a datum; null for all other data types. The maximum octet length depends on the declared character maximum length (see above) and the server encoding.
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Name of the database containing the collation of the domain (always the current database), null if default or the data type of the domain is not collatable
collation_schema `sql_identifier` Name of the schema containing the collation of the domain, null if default or the data type of the domain is not collatable
collation_name `sql_identifier` Name of the collation of the domain, null if default or the data type of the domain is not collatable
numeric_precision `cardinal_number` If the domain has a numeric type, this column contains the (declared or implicit) precision of the type for this domain. The precision indicates the number of significant digits. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`. For all other data types, this column is null.
numeric_precision_radix `cardinal_number` If the domain has a numeric type, this column indicates in which base the values in the columns `numeric_precision` and `numeric_scale` are expressed. The value is either 2 or 10. For all other data types, this column is null.
numeric_scale `cardinal_number` If the domain has an exact numeric type, this column contains the (declared or implicit) scale of the type for this domain. The scale indicates the number of significant digits to the right of the decimal point. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`. For all other data types, this column is null.
datetime_precision `cardinal_number` If `data_type` identifies a date, time, timestamp, or interval type, this column contains the (declared or implicit) fractional seconds precision of the type for this domain, that is, the number of decimal digits maintained following the decimal point in the seconds value. For all other data types, this column is null.
interval_type `character_data` If `data_type` identifies an interval type, this column contains the specification which fields the intervals include for this domain, e.g., `YEAR TO MONTH`, `DAY TO SECOND`, etc. If no field restrictions were specified (that is, the interval accepts all fields), and for all other data types, this field is null.
interval_precision `cardinal_number` Applies to a feature not available in PostgreSQL (see `datetime_precision` for the fractional seconds precision of interval type domains)
domain_default `character_data` Default expression of the domain
udt_catalog `sql_identifier` Name of the database that the domain data type is defined in (always the current database)
udt_schema `sql_identifier` Name of the schema that the domain data type is defined in
udt_name `sql_identifier` Name of the domain data type
scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
maximum_cardinality `cardinal_number` Always null, because arrays always have unlimited maximum cardinality in PostgreSQL
dtd_identifier `sql_identifier` An identifier of the data type descriptor of the domain, unique among the data type descriptors pertaining to the domain (which is trivial, because a domain only contains one data type descriptor). This is mainly useful for joining with other instances of such identifiers. (The specific format of the identifier is not defined and not guaranteed to remain the same in future versions.)

## `element_types`

The view `element_types` contains the data type descriptors of the elements of arrays. When a table column, composite-type attribute, domain, function parameter, or function return value is defined to be of an array type, the respective information schema view only contains `ARRAY` in the column `data_type`. To obtain information on the element type of the array, you can join the respective view with this view. For example, to show the columns of a table with data types and array element types, if applicable, you could do:

    SELECT c.column_name, c.data_type, e.data_type AS element_type
    FROM information_schema.columns c LEFT JOIN information_schema.element_types e
         ON ((c.table_catalog, c.table_schema, c.table_name, 'TABLE', c.dtd_identifier)
           = (e.object_catalog, e.object_schema, e.object_name, e.object_type, e.collection_type_identifier))
    WHERE c.table_schema = '...' AND c.table_name = '...'
    ORDER BY c.ordinal_position;

This view only includes objects that the current user has access to, by way of being the owner or having some privilege.

## element_types Columns

Column Type Description
object_catalog `sql_identifier` Name of the database that contains the object that uses the array being described (always the current database)
object_schema `sql_identifier` Name of the schema that contains the object that uses the array being described
object_name `sql_identifier` Name of the object that uses the array being described
object_type `character_data` The type of the object that uses the array being described: one of `TABLE` (the array is used by a column of that table), `USER-DEFINED TYPE` (the array is used by an attribute of that composite type), `DOMAIN` (the array is used by that domain), `ROUTINE` (the array is used by a parameter or the return data type of that function).
collection_type_identifier `sql_identifier` The identifier of the data type descriptor of the array being described. Use this to join with the `dtd_identifier` columns of other information schema views.
data_type `character_data` Data type of the array elements, if it is a built-in type, else `USER-DEFINED` (in that case, the type is identified in `udt_name` and associated columns).
character_maximum_length `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
character_octet_length `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Name of the database containing the collation of the element type (always the current database), null if default or the data type of the element is not collatable
collation_schema `sql_identifier` Name of the schema containing the collation of the element type, null if default or the data type of the element is not collatable
collation_name `sql_identifier` Name of the collation of the element type, null if default or the data type of the element is not collatable
numeric_precision `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
numeric_precision_radix `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
numeric_scale `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
datetime_precision `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
interval_type `character_data` Always null, since this information is not applied to array element data types in PostgreSQL
interval_precision `cardinal_number` Always null, since this information is not applied to array element data types in PostgreSQL
udt_catalog `sql_identifier` Name of the database that the data type of the elements is defined in (always the current database)
udt_schema `sql_identifier` Name of the schema that the data type of the elements is defined in
udt_name `sql_identifier` Name of the data type of the elements
scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
maximum_cardinality `cardinal_number` Always null, because arrays always have unlimited maximum cardinality in PostgreSQL
dtd_identifier `sql_identifier` An identifier of the data type descriptor of the element. This is currently not useful.

## `enabled_roles`

The view `enabled_roles` identifies the currently enabled roles. The enabled roles are recursively defined as the current user together with all roles that have been granted to the enabled roles with automatic inheritance. In other words, these are all roles that the current user has direct or indirect, automatically inheriting membership in.

For permission checking, the set of applicable roles is applied, which can be broader than the set of enabled roles. So generally, it is better to use the view `applicable_roles` instead of this one; See infoschema-applicable-roles for details on `applicable_roles` view.

## enabled_roles Columns

Column Type Description
role_name `sql_identifier` Name of a role

## `foreign_data_wrapper_options`

The view `foreign_data_wrapper_options` contains all the options defined for foreign-data wrappers in the current database. Only those foreign-data wrappers are shown that the current user has access to (by way of being the owner or having some privilege).

## foreign_data_wrapper_options Columns

Column Type Description
foreign_data_wrapper_catalog `sql_identifier` Name of the database that the foreign-data wrapper is defined in (always the current database)
foreign_data_wrapper_name `sql_identifier` Name of the foreign-data wrapper
option_name `sql_identifier` Name of an option
option_value `character_data` Value of the option

## `foreign_data_wrappers`

The view `foreign_data_wrappers` contains all foreign-data wrappers defined in the current database. Only those foreign-data wrappers are shown that the current user has access to (by way of being the owner or having some privilege).

## foreign_data_wrappers Columns

Column Type Description
foreign_data_wrapper_catalog `sql_identifier` Name of the database that contains the foreign-data wrapper (always the current database)
foreign_data_wrapper_name `sql_identifier` Name of the foreign-data wrapper
authorization_identifier `sql_identifier` Name of the owner of the foreign server
library_name `character_data` File name of the library that implementing this foreign-data wrapper
foreign_data_wrapper_language `character_data` Language used to implement this foreign-data wrapper

## `foreign_server_options`

The view `foreign_server_options` contains all the options defined for foreign servers in the current database. Only those foreign servers are shown that the current user has access to (by way of being the owner or having some privilege).

## foreign_server_options Columns

Column Type Description
foreign_server_catalog `sql_identifier` Name of the database that the foreign server is defined in (always the current database)
foreign_server_name `sql_identifier` Name of the foreign server
option_name `sql_identifier` Name of an option
option_value `character_data` Value of the option

## `foreign_servers`

The view `foreign_servers` contains all foreign servers defined in the current database. Only those foreign servers are shown that the current user has access to (by way of being the owner or having some privilege).

## foreign_servers Columns

Column Type Description
foreign_server_catalog `sql_identifier` Name of the database that the foreign server is defined in (always the current database)
foreign_server_name `sql_identifier` Name of the foreign server
foreign_data_wrapper_catalog `sql_identifier` Name of the database that contains the foreign-data wrapper used by the foreign server (always the current database)
foreign_data_wrapper_name `sql_identifier` Name of the foreign-data wrapper used by the foreign server
foreign_server_type `character_data` Foreign server type information, if specified upon creation
foreign_server_version `character_data` Foreign server version information, if specified upon creation
authorization_identifier `sql_identifier` Name of the owner of the foreign server

## `foreign_table_options`

The view `foreign_table_options` contains all the options defined for foreign tables in the current database. Only those foreign tables are shown that the current user has access to (by way of being the owner or having some privilege).

## foreign_table_options Columns

Column Type Description
foreign_table_catalog `sql_identifier` Name of the database that contains the foreign table (always the current database)
foreign_table_schema `sql_identifier` Name of the schema that contains the foreign table
foreign_table_name `sql_identifier` Name of the foreign table
option_name `sql_identifier` Name of an option
option_value `character_data` Value of the option

## `foreign_tables`

The view `foreign_tables` contains all foreign tables defined in the current database. Only those foreign tables are shown that the current user has access to (by way of being the owner or having some privilege).

## foreign_tables Columns

Column Type Description
foreign_table_catalog `sql_identifier` Name of the database that the foreign table is defined in (always the current database)
foreign_table_schema `sql_identifier` Name of the schema that contains the foreign table
foreign_table_name `sql_identifier` Name of the foreign table
foreign_server_catalog `sql_identifier` Name of the database that the foreign server is defined in (always the current database)
foreign_server_name `sql_identifier` Name of the foreign server

## `key_column_usage`

The view `key_column_usage` identifies all columns in the current database that are restricted by some unique, primary key, or foreign key constraint. Check constraints are not included in this view. Only those columns are shown that the current user has access to, by way of being the owner or having some privilege.

## key_column_usage Columns

Column Type Description
constraint_catalog `sql_identifier` Name of the database that contains the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema that contains the constraint
constraint_name `sql_identifier` Name of the constraint
table_catalog `sql_identifier` Name of the database that contains the table that contains the column that is restricted by this constraint (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that contains the column that is restricted by this constraint
table_name `sql_identifier` Name of the table that contains the column that is restricted by this constraint
column_name `sql_identifier` Name of the column that is restricted by this constraint
ordinal_position `cardinal_number` Ordinal position of the column within the constraint key (count starts at 1)
position_in_unique_constraint `cardinal_number` For a foreign-key constraint, ordinal position of the referenced column within its unique constraint (count starts at 1); otherwise null

## `parameters`

The view `parameters` contains information about the parameters (arguments) of all functions in the current database. Only those functions are shown that the current user has access to (by way of being the owner or having some privilege).

## parameters Columns

Column Type Description
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
ordinal_position `cardinal_number` Ordinal position of the parameter in the argument list of the function (count starts at 1)
parameter_mode `character_data` `IN` for input parameter, `OUT` for output parameter, and `INOUT` for input/output parameter.
is_result `yes_or_no` Applies to a feature not available in PostgreSQL
as_locator `yes_or_no` Applies to a feature not available in PostgreSQL
parameter_name `sql_identifier` Name of the parameter, or null if the parameter has no name
data_type `character_data` Data type of the parameter, if it is a built-in type, or `ARRAY` if it is some array (in that case, see the view `element_types`), else `USER-DEFINED` (in that case, the type is identified in `udt_name` and associated columns).
character_maximum_length `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
character_octet_length `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Always null, since this information is not applied to parameter data types in PostgreSQL
collation_schema `sql_identifier` Always null, since this information is not applied to parameter data types in PostgreSQL
collation_name `sql_identifier` Always null, since this information is not applied to parameter data types in PostgreSQL
numeric_precision `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
numeric_precision_radix `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
numeric_scale `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
datetime_precision `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
interval_type `character_data` Always null, since this information is not applied to parameter data types in PostgreSQL
interval_precision `cardinal_number` Always null, since this information is not applied to parameter data types in PostgreSQL
udt_catalog `sql_identifier` Name of the database that the data type of the parameter is defined in (always the current database)
udt_schema `sql_identifier` Name of the schema that the data type of the parameter is defined in
udt_name `sql_identifier` Name of the data type of the parameter
scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
maximum_cardinality `cardinal_number` Always null, because arrays always have unlimited maximum cardinality in PostgreSQL
dtd_identifier `sql_identifier` An identifier of the data type descriptor of the parameter, unique among the data type descriptors pertaining to the function. This is mainly useful for joining with other instances of such identifiers. (The specific format of the identifier is not defined and not guaranteed to remain the same in future versions.)
parameter_default `character_data` The default expression of the parameter, or null if none or if the function is not owned by a currently enabled role.

## `referential_constraints`

The view `referential_constraints` contains all referential (foreign key) constraints in the current database. Only those constraints are shown for which the current user has write access to the referencing table (by way of being the owner or having some privilege other than `SELECT`).

## referential_constraints Columns

Column Type Description
constraint_catalog `sql_identifier` Name of the database containing the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema containing the constraint
constraint_name `sql_identifier` Name of the constraint
unique_constraint_catalog `sql_identifier` Name of the database that contains the unique or primary key constraint that the foreign key constraint references (always the current database)
unique_constraint_schema `sql_identifier` Name of the schema that contains the unique or primary key constraint that the foreign key constraint references
unique_constraint_name `sql_identifier` Name of the unique or primary key constraint that the foreign key constraint references
match_option `character_data` Match option of the foreign key constraint: `FULL`, `PARTIAL`, or `NONE`.
update_rule `character_data` Update rule of the foreign key constraint: `CASCADE`, `SET NULL`, `SET DEFAULT`, `RESTRICT`, or `NO ACTION`.
delete_rule `character_data` Delete rule of the foreign key constraint: `CASCADE`, `SET NULL`, `SET DEFAULT`, `RESTRICT`, or `NO ACTION`.

## `role_column_grants`

The view `role_column_grants` identifies all privileges granted on columns where the grantor or grantee is a currently enabled role. Further information can be found under `column_privileges`. The only effective difference between this view and `column_privileges` is that this view omits columns that have been made accessible to the current user by way of a grant to `PUBLIC`.

## role_column_grants Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
table_catalog `sql_identifier` Name of the database that contains the table that contains the column (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that contains the column
table_name `sql_identifier` Name of the table that contains the column
column_name `sql_identifier` Name of the column
privilege_type `character_data` Type of the privilege: `SELECT`, `INSERT`, `UPDATE`, or `REFERENCES`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `role_routine_grants`

The view `role_routine_grants` identifies all privileges granted on functions where the grantor or grantee is a currently enabled role. Further information can be found under `routine_privileges`. The only effective difference between this view and `routine_privileges` is that this view omits functions that have been made accessible to the current user by way of a grant to `PUBLIC`.

## role_routine_grants Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
routine_catalog `sql_identifier` Name of the database containing the function (always the current database)
routine_schema `sql_identifier` Name of the schema containing the function
routine_name `sql_identifier` Name of the function (might be duplicated in case of overloading)
privilege_type `character_data` Always `EXECUTE` (the only privilege type for functions)
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `role_table_grants`

The view `role_table_grants` identifies all privileges granted on tables or views where the grantor or grantee is a currently enabled role. Further information can be found under `table_privileges`. The only effective difference between this view and `table_privileges` is that this view omits tables that have been made accessible to the current user by way of a grant to `PUBLIC`.

## role_table_grants Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
table_catalog `sql_identifier` Name of the database that contains the table (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table
table_name `sql_identifier` Name of the table
privilege_type `character_data` Type of the privilege: `SELECT`, `INSERT`, `UPDATE`, `DELETE`, `TRUNCATE`, `REFERENCES`, or `TRIGGER`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not
with_hierarchy `yes_or_no` In the SQL standard, `WITH HIERARCHY OPTION` is a separate (sub-)privilege allowing certain operations on table inheritance hierarchies. In PostgreSQL, this is included in the `SELECT` privilege, so this column shows `YES` if the privilege is `SELECT`, else `NO`.

## `role_udt_grants`

The view `role_udt_grants` is intended to identify `USAGE` privileges granted on user-defined types where the grantor or grantee is a currently enabled role. Further information can be found under `udt_privileges`. The only effective difference between this view and `udt_privileges` is that this view omits objects that have been made accessible to the current user by way of a grant to `PUBLIC`. Since data types do not have real privileges in PostgreSQL, but only an implicit grant to `PUBLIC`, this view is empty.

## role_udt_grants Columns

Column Type Description
grantor `sql_identifier` The name of the role that granted the privilege
grantee `sql_identifier` The name of the role that the privilege was granted to
udt_catalog `sql_identifier` Name of the database containing the type (always the current database)
udt_schema `sql_identifier` Name of the schema containing the type
udt_name `sql_identifier` Name of the type
privilege_type `character_data` Always `TYPE USAGE`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `role_usage_grants`

The view `role_usage_grants` identifies `USAGE` privileges granted on various kinds of objects where the grantor or grantee is a currently enabled role. Further information can be found under `usage_privileges`. The only effective difference between this view and `usage_privileges` is that this view omits objects that have been made accessible to the current user by way of a grant to `PUBLIC`.

## role_usage_grants Columns

Column Type Description
grantor `sql_identifier` The name of the role that granted the privilege
grantee `sql_identifier` The name of the role that the privilege was granted to
object_catalog `sql_identifier` Name of the database containing the object (always the current database)
object_schema `sql_identifier` Name of the schema containing the object, if applicable, else an empty string
object_name `sql_identifier` Name of the object
object_type `character_data` `COLLATION` or `DOMAIN` or `FOREIGN DATA WRAPPER` or `FOREIGN SERVER` or `SEQUENCE`
privilege_type `character_data` Always `USAGE`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `routine_column_usage`

The view `routine_column_usage` identifies all columns that are used by a function or procedure, either in the SQL body or in parameter default expressions. (This only works for unquoted SQL bodies, not quoted bodies or functions in other languages.) A column is only included if its table is owned by a currently enabled role.

## `routine_column_usage` Columns

Column Type Description
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
routine_catalog `sql_identifier` Name of the database containing the function (always the current database)
routine_schema `sql_identifier` Name of the schema containing the function
routine_name `sql_identifier` Name of the function (might be duplicated in case of overloading)
table_catalog `sql_identifier` Name of the database that contains the table that is used by the function (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that is used by the function
table_name `sql_identifier` Name of the table that is used by the function
column_name `sql_identifier` Name of the column that is used by the function

## `routine_privileges`

The view `routine_privileges` identifies all privileges granted on functions to a currently enabled role or by a currently enabled role. There is one row for each combination of function, grantor, and grantee.

## routine_privileges Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
routine_catalog `sql_identifier` Name of the database containing the function (always the current database)
routine_schema `sql_identifier` Name of the schema containing the function
routine_name `sql_identifier` Name of the function (might be duplicated in case of overloading)
privilege_type `character_data` Always `EXECUTE` (the only privilege type for functions)
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `routine_routine_usage`

The view `routine_routine_usage` identifies all functions or procedures that are used by another (or the same) function or procedure, either in the SQL body or in parameter default expressions. (This only works for unquoted SQL bodies, not quoted bodies or functions in other languages.) An entry is included here only if the used function is owned by a currently enabled role. (There is no such restriction on the using function.)

Note that the entries for both functions in the view refer to the specific name of the routine, even though the column names are used in a way that is inconsistent with other information schema views about routines. This is per SQL standard, although it is arguably a misdesign. See infoschema-routines for more information about specific names.

## `routine_routine_usage` Columns

Column Type Description
specific_catalog `sql_identifier` Name of the database containing the using function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the using function
specific_name `sql_identifier` The specific name of the using function.
routine_catalog `sql_identifier` Name of the database that contains the function that is used by the first function (always the current database)
routine_schema `sql_identifier` Name of the schema that contains the function that is used by the first function
routine_name `sql_identifier` The specific name of the function that is used by the first function.

## `routine_sequence_usage`

The view `routine_sequence_usage` identifies all sequences that are used by a function or procedure, either in the SQL body or in parameter default expressions. (This only works for unquoted SQL bodies, not quoted bodies or functions in other languages.) A sequence is only included if that sequence is owned by a currently enabled role.

## `routine_sequence_usage` Columns

Column Type Description
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
routine_catalog `sql_identifier` Name of the database containing the function (always the current database)
routine_schema `sql_identifier` Name of the schema containing the function
routine_name `sql_identifier` Name of the function (might be duplicated in case of overloading)
schema_catalog `sql_identifier` Name of the database that contains the sequence that is used by the function (always the current database)
sequence_schema `sql_identifier` Name of the schema that contains the sequence that is used by the function
sequence_name `sql_identifier` Name of the sequence that is used by the function

## `routine_table_usage`

The view `routine_table_usage` is meant to identify all tables that are used by a function or procedure. This information is currently not tracked by PostgreSQL.

## `routine_table_usage` Columns

Column Type Description
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
routine_catalog `sql_identifier` Name of the database containing the function (always the current database)
routine_schema `sql_identifier` Name of the schema containing the function
routine_name `sql_identifier` Name of the function (might be duplicated in case of overloading)
table_catalog `sql_identifier` Name of the database that contains the table that is used by the function (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that is used by the function
table_name `sql_identifier` Name of the table that is used by the function

## `routines`

The view `routines` contains all functions and procedures in the current database. Only those functions and procedures are shown that the current user has access to (by way of being the owner or having some privilege).

## routines Columns

Column Type Description
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. This is a name that uniquely identifies the function in the schema, even if the real name of the function is overloaded. The format of the specific name is not defined, it should only be used to compare it to other instances of specific routine names.
routine_catalog `sql_identifier` Name of the database containing the function (always the current database)
routine_schema `sql_identifier` Name of the schema containing the function
routine_name `sql_identifier` Name of the function (might be duplicated in case of overloading)
routine_type `character_data` `FUNCTION` for a function, `PROCEDURE` for a procedure
module_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
module_schema `sql_identifier` Applies to a feature not available in PostgreSQL
module_name `sql_identifier` Applies to a feature not available in PostgreSQL
udt_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
udt_schema `sql_identifier` Applies to a feature not available in PostgreSQL
udt_name `sql_identifier` Applies to a feature not available in PostgreSQL
data_type `character_data` Return data type of the function, if it is a built-in type, or `ARRAY` if it is some array (in that case, see the view `element_types`), else `USER-DEFINED` (in that case, the type is identified in `type_udt_name` and associated columns). Null for a procedure.
character_maximum_length `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
character_octet_length `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Always null, since this information is not applied to return data types in PostgreSQL
collation_schema `sql_identifier` Always null, since this information is not applied to return data types in PostgreSQL
collation_name `sql_identifier` Always null, since this information is not applied to return data types in PostgreSQL
numeric_precision `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
numeric_precision_radix `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
numeric_scale `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
datetime_precision `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
interval_type `character_data` Always null, since this information is not applied to return data types in PostgreSQL
interval_precision `cardinal_number` Always null, since this information is not applied to return data types in PostgreSQL
type_udt_catalog `sql_identifier` Name of the database that the return data type of the function is defined in (always the current database). Null for a procedure.
type_udt_schema `sql_identifier` Name of the schema that the return data type of the function is defined in. Null for a procedure.
type_udt_name `sql_identifier` Name of the return data type of the function. Null for a procedure.
scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
maximum_cardinality `cardinal_number` Always null, because arrays always have unlimited maximum cardinality in PostgreSQL
dtd_identifier `sql_identifier` An identifier of the data type descriptor of the return data type of this function, unique among the data type descriptors pertaining to the function. This is mainly useful for joining with other instances of such identifiers. (The specific format of the identifier is not defined and not guaranteed to remain the same in future versions.)
routine_body `character_data` If the function is an SQL function, then `SQL`, else `EXTERNAL`.
routine_definition `character_data` The source text of the function (null if the function is not owned by a currently enabled role). (According to the SQL standard, this column is only applicable if `routine_body` is `SQL`, but in PostgreSQL it will contain whatever source text was specified when the function was created.)
external_name `character_data` If this function is a C function, then the external name (link symbol) of the function; else null. (This works out to be the same value that is shown in `routine_definition`.)
external_language `character_data` The language the function is written in
parameter_style `character_data` Always `GENERAL` (The SQL standard defines other parameter styles, which are not available in PostgreSQL.)
is_deterministic `yes_or_no` If the function is declared immutable (called deterministic in the SQL standard), then `YES`, else `NO`. (You cannot query the other volatility levels available in PostgreSQL through the information schema.)
sql_data_access `character_data` Always `MODIFIES`, meaning that the function possibly modifies SQL data. This information is not useful for PostgreSQL.
is_null_call `yes_or_no` If the function automatically returns null if any of its arguments are null, then `YES`, else `NO`. Null for a procedure.
sql_path `character_data` Applies to a feature not available in PostgreSQL
schema_level_routine `yes_or_no` Always `YES` (The opposite would be a method of a user-defined type, which is a feature not available in PostgreSQL.)
max_dynamic_result_sets `cardinal_number` Applies to a feature not available in PostgreSQL
is_user_defined_cast `yes_or_no` Applies to a feature not available in PostgreSQL
is_implicitly_invocable `yes_or_no` Applies to a feature not available in PostgreSQL
security_type `character_data` If the function runs with the privileges of the current user, then `INVOKER`, if the function runs with the privileges of the user who defined it, then `DEFINER`.
to_sql_specific_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
to_sql_specific_schema `sql_identifier` Applies to a feature not available in PostgreSQL
to_sql_specific_name `sql_identifier` Applies to a feature not available in PostgreSQL
as_locator `yes_or_no` Applies to a feature not available in PostgreSQL
created `time_stamp` Applies to a feature not available in PostgreSQL
last_altered `time_stamp` Applies to a feature not available in PostgreSQL
new_savepoint_level `yes_or_no` Applies to a feature not available in PostgreSQL
is_udt_dependent `yes_or_no` Currently always `NO`. The alternative `YES` applies to a feature not available in PostgreSQL.
result_cast_from_data_type `character_data` Applies to a feature not available in PostgreSQL
result_cast_as_locator `yes_or_no` Applies to a feature not available in PostgreSQL
result_cast_char_max_length `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_char_octet_length `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_char_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_char_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_char_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_collation_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_collation_schema `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_collation_name `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_numeric_precision `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_numeric_precision_radix `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_numeric_scale `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_datetime_precision `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_interval_type `character_data` Applies to a feature not available in PostgreSQL
result_cast_interval_precision `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_type_udt_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_type_udt_schema `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_type_udt_name `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_scope_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_scope_schema `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_scope_name `sql_identifier` Applies to a feature not available in PostgreSQL
result_cast_maximum_cardinality `cardinal_number` Applies to a feature not available in PostgreSQL
result_cast_dtd_identifier `sql_identifier` Applies to a feature not available in PostgreSQL

## `schemata`

The view `schemata` contains all schemas in the current database that the current user has access to (by way of being the owner or having some privilege).

## schemata Columns

Column Type Description
catalog_name `sql_identifier` Name of the database that the schema is contained in (always the current database)
schema_name `sql_identifier` Name of the schema
schema_owner `sql_identifier` Name of the owner of the schema
default_character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
default_character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
default_character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
sql_path `character_data` Applies to a feature not available in PostgreSQL

## `sequences`

The view `sequences` contains all sequences defined in the current database. Only those sequences are shown that the current user has access to (by way of being the owner or having some privilege).

## sequences Columns

Column Type Description
sequence_catalog `sql_identifier` Name of the database that contains the sequence (always the current database)
sequence_schema `sql_identifier` Name of the schema that contains the sequence
sequence_name `sql_identifier` Name of the sequence
data_type `character_data` The data type of the sequence.
numeric_precision `cardinal_number` This column contains the (declared or implicit) precision of the sequence data type (see above). The precision indicates the number of significant digits. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`.
numeric_precision_radix `cardinal_number` This column indicates in which base the values in the columns `numeric_precision` and `numeric_scale` are expressed. The value is either 2 or 10.
numeric_scale `cardinal_number` This column contains the (declared or implicit) scale of the sequence data type (see above). The scale indicates the number of significant digits to the right of the decimal point. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column `numeric_precision_radix`.
start_value `character_data` The start value of the sequence
minimum_value `character_data` The minimum value of the sequence
maximum_value `character_data` The maximum value of the sequence
increment `character_data` The increment of the sequence
cycle_option `yes_or_no` `YES` if the sequence cycles, else `NO`

Note that in accordance with the SQL standard, the start, minimum, maximum, and increment values are returned as character strings.

## `sql_features`

The table `sql_features` contains information about which formal features defined in the SQL standard are supported by PostgreSQL. This is the same information that is presented in features. There you can also find some additional background information.

## sql_features Columns

Column Type Description
feature_id `character_data` Identifier string of the feature
feature_name `character_data` Descriptive name of the feature
sub_feature_id `character_data` Identifier string of the subfeature, or a zero-length string if not a subfeature
sub_feature_name `character_data` Descriptive name of the subfeature, or a zero-length string if not a subfeature
is_supported `yes_or_no` `YES` if the feature is fully supported by the current version of PostgreSQL, `NO` if not
is_verified_by `character_data` Always null, since the PostgreSQL development group does not perform formal testing of feature conformance
comments `character_data` Possibly a comment about the supported status of the feature

## `sql_implementation_info`

The table `sql_implementation_info` contains information about various aspects that are left implementation-defined by the SQL standard. This information is primarily intended for use in the context of the ODBC interface; users of other interfaces will probably find this information to be of little use. For this reason, the individual implementation information items are not described here; you will find them in the description of the ODBC interface.

## sql_implementation_info Columns

Column Type Description
implementation_info_id `character_data` Identifier string of the implementation information item
implementation_info_name `character_data` Descriptive name of the implementation information item
integer_value `cardinal_number` Value of the implementation information item, or null if the value is contained in the column `character_value`
character_value `character_data` Value of the implementation information item, or null if the value is contained in the column `integer_value`
comments `character_data` Possibly a comment pertaining to the implementation information item

## `sql_parts`

The table `sql_parts` contains information about which of the several parts of the SQL standard are supported by PostgreSQL.

## sql_parts Columns

Column Type Description
feature_id `character_data` An identifier string containing the number of the part
feature_name `character_data` Descriptive name of the part
is_supported `yes_or_no` `YES` if the part is fully supported by the current version of PostgreSQL, `NO` if not
is_verified_by `character_data` Always null, since the PostgreSQL development group does not perform formal testing of feature conformance
comments `character_data` Possibly a comment about the supported status of the part

## `sql_sizing`

The table `sql_sizing` contains information about various size limits and maximum values in PostgreSQL. This information is primarily intended for use in the context of the ODBC interface; users of other interfaces will probably find this information to be of little use. For this reason, the individual sizing items are not described here; you will find them in the description of the ODBC interface.

## sql_sizing Columns

Column Type Description
sizing_id `cardinal_number` Identifier of the sizing item
sizing_name `character_data` Descriptive name of the sizing item
supported_value `cardinal_number` Value of the sizing item, or 0 if the size is unlimited or cannot be determined, or null if the features for which the sizing item is applicable are not supported
comments `character_data` Possibly a comment pertaining to the sizing item

## `table_constraints`

The view `table_constraints` contains all constraints belonging to tables that the current user owns or has some privilege other than `SELECT` on.

## table_constraints Columns

Column Type Description
constraint_catalog `sql_identifier` Name of the database that contains the constraint (always the current database)
constraint_schema `sql_identifier` Name of the schema that contains the constraint
constraint_name `sql_identifier` Name of the constraint
table_catalog `sql_identifier` Name of the database that contains the table (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table
table_name `sql_identifier` Name of the table
constraint_type `character_data` Type of the constraint: `CHECK` (includes not-null constraints), `FOREIGN KEY`, `PRIMARY KEY`, or `UNIQUE`
is_deferrable `yes_or_no` `YES` if the constraint is deferrable, `NO` if not
initially_deferred `yes_or_no` `YES` if the constraint is deferrable and initially deferred, `NO` if not
enforced `yes_or_no` `YES` if the constraint is enforced, `NO` if not
nulls_distinct `yes_or_no` If the constraint is a unique constraint, then `YES` if the constraint treats nulls as distinct or `NO` if it treats nulls as not distinct, otherwise null for other types of constraints.

## `table_privileges`

The view `table_privileges` identifies all privileges granted on tables or views to a currently enabled role or by a currently enabled role. There is one row for each combination of table, grantor, and grantee.

## table_privileges Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
table_catalog `sql_identifier` Name of the database that contains the table (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table
table_name `sql_identifier` Name of the table
privilege_type `character_data` Type of the privilege: `SELECT`, `INSERT`, `UPDATE`, `DELETE`, `TRUNCATE`, `REFERENCES`, or `TRIGGER`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not
with_hierarchy `yes_or_no` In the SQL standard, `WITH HIERARCHY OPTION` is a separate (sub-)privilege allowing certain operations on table inheritance hierarchies. In PostgreSQL, this is included in the `SELECT` privilege, so this column shows `YES` if the privilege is `SELECT`, else `NO`.

## `tables`

The view `tables` contains all tables and views defined in the current database. Only those tables and views are shown that the current user has access to (by way of being the owner or having some privilege).

## tables Columns

Column Type Description
table_catalog `sql_identifier` Name of the database that contains the table (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table
table_name `sql_identifier` Name of the table
table_type `character_data` Type of the table: `BASE TABLE` for a persistent base table (the normal table type), `VIEW` for a view, `FOREIGN` for a foreign table, or `LOCAL TEMPORARY` for a temporary table
self_referencing_column_name `sql_identifier` Applies to a feature not available in PostgreSQL
reference_generation `character_data` Applies to a feature not available in PostgreSQL
user_defined_type_catalog `sql_identifier` If the table is a typed table, the name of the database that contains the underlying data type (always the current database), else null.
user_defined_type_schema `sql_identifier` If the table is a typed table, the name of the schema that contains the underlying data type, else null.
user_defined_type_name `sql_identifier` If the table is a typed table, the name of the underlying data type, else null.
is_insertable_into `yes_or_no` `YES` if the table is insertable into, `NO` if not (Base tables are always insertable into, views not necessarily.)
is_typed `yes_or_no` `YES` if the table is a typed table, `NO` if not
commit_action `character_data` Not yet implemented

## `transforms`

The view `transforms` contains information about the transforms defined in the current database. More precisely, it contains a row for each function contained in a transform (the from SQL or to SQL function).

## transforms Columns

Column Type Description
udt_catalog `sql_identifier` Name of the database that contains the type the transform is for (always the current database)
udt_schema `sql_identifier` Name of the schema that contains the type the transform is for
udt_name `sql_identifier` Name of the type the transform is for
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.
group_name `sql_identifier` The SQL standard allows defining transforms in groups, and selecting a group at run time. PostgreSQL does not support this. Instead, transforms are specific to a language. As a compromise, this field contains the language the transform is for.
transform_type `character_data` `FROM SQL` or `TO SQL`

## `triggered_update_columns`

For triggers in the current database that specify a column list (like `UPDATE OF column1, column2`), the view `triggered_update_columns` identifies these columns. Triggers that do not specify a column list are not included in this view. Only those columns are shown that the current user owns or has some privilege other than `SELECT` on.

## triggered_update_columns Columns

Column Type Description
trigger_catalog `sql_identifier` Name of the database that contains the trigger (always the current database)
trigger_schema `sql_identifier` Name of the schema that contains the trigger
trigger_name `sql_identifier` Name of the trigger
event_object_catalog `sql_identifier` Name of the database that contains the table that the trigger is defined on (always the current database)
event_object_schema `sql_identifier` Name of the schema that contains the table that the trigger is defined on
event_object_table `sql_identifier` Name of the table that the trigger is defined on
event_object_column `sql_identifier` Name of the column that the trigger is defined on

## `triggers`

The view `triggers` contains all triggers defined in the current database on tables and views that the current user owns or has some privilege other than `SELECT` on.

## triggers Columns

Column Type Description
trigger_catalog `sql_identifier` Name of the database that contains the trigger (always the current database)
trigger_schema `sql_identifier` Name of the schema that contains the trigger
trigger_name `sql_identifier` Name of the trigger
event_manipulation `character_data` Event that fires the trigger (`INSERT`, `UPDATE`, or `DELETE`)
event_object_catalog `sql_identifier` Name of the database that contains the table that the trigger is defined on (always the current database)
event_object_schema `sql_identifier` Name of the schema that contains the table that the trigger is defined on
event_object_table `sql_identifier` Name of the table that the trigger is defined on
action_order `cardinal_number` Firing order among triggers on the same table having the same `event_manipulation`, `action_timing`, and `action_orientation`. In PostgreSQL, triggers are fired in name order, so this column reflects that.
action_condition `character_data` `WHEN` condition of the trigger, null if none (also null if the table is not owned by a currently enabled role)
action_statement `character_data` Statement that is executed by the trigger (currently always `EXECUTE FUNCTION `function`(...)`)
action_orientation `character_data` Identifies whether the trigger fires once for each processed row or once for each statement (`ROW` or `STATEMENT`)
action_timing `character_data` Time at which the trigger fires (`BEFORE`, `AFTER`, or `INSTEAD OF`)
action_reference_old_table `sql_identifier` Name of the old transition table, or null if none
action_reference_new_table `sql_identifier` Name of the new transition table, or null if none
action_reference_old_row `sql_identifier` Applies to a feature not available in PostgreSQL
action_reference_new_row `sql_identifier` Applies to a feature not available in PostgreSQL
created `time_stamp` Applies to a feature not available in PostgreSQL

Triggers in PostgreSQL have two incompatibilities with the SQL standard that affect the representation in the information schema. First, trigger names are local to each table in PostgreSQL, rather than being independent schema objects. Therefore there can be duplicate trigger names defined in one schema, so long as they belong to different tables. (`trigger_catalog` and `trigger_schema` are really the values pertaining to the table that the trigger is defined on.) Second, triggers can be defined to fire on multiple events in PostgreSQL (e.g., `ON INSERT OR UPDATE`), whereas the SQL standard only allows one. If a trigger is defined to fire on multiple events, it is represented as multiple rows in the information schema, one for each type of event. As a consequence of these two issues, the primary key of the view `triggers` is really `(trigger_catalog, trigger_schema, event_object_table, trigger_name, event_manipulation)` instead of `(trigger_catalog, trigger_schema, trigger_name)`, which is what the SQL standard specifies. Nonetheless, if you define your triggers in a manner that conforms with the SQL standard (trigger names unique in the schema and only one event type per trigger), this will not affect you.

Prior to PostgreSQL 9.1, this view's columns action_timing, action_reference_old_table, action_reference_new_table, action_reference_old_row, and action_reference_new_row were named condition_timing, condition_reference_old_table, condition_reference_new_table, condition_reference_old_row, and condition_reference_new_row respectively. That was how they were named in the SQL:1999 standard. The new naming conforms to SQL:2003 and later.

## `udt_privileges`

The view `udt_privileges` identifies `USAGE` privileges granted on user-defined types to a currently enabled role or by a currently enabled role. There is one row for each combination of type, grantor, and grantee. This view shows only composite types (see under infoschema-user-defined-types for why); see infoschema-usage-privileges for domain privileges.

## udt_privileges Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
udt_catalog `sql_identifier` Name of the database containing the type (always the current database)
udt_schema `sql_identifier` Name of the schema containing the type
udt_name `sql_identifier` Name of the type
privilege_type `character_data` Always `TYPE USAGE`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `usage_privileges`

The view `usage_privileges` identifies `USAGE` privileges granted on various kinds of objects to a currently enabled role or by a currently enabled role. In PostgreSQL, this currently applies to collations, domains, foreign-data wrappers, foreign servers, and sequences. There is one row for each combination of object, grantor, and grantee.

Since collations do not have real privileges in PostgreSQL, this view shows implicit non-grantable `USAGE` privileges granted by the owner to `PUBLIC` for all collations. The other object types, however, show real privileges.

In PostgreSQL, sequences also support `SELECT` and `UPDATE` privileges in addition to the `USAGE` privilege. These are nonstandard and therefore not visible in the information schema.

## usage_privileges Columns

Column Type Description
grantor `sql_identifier` Name of the role that granted the privilege
grantee `sql_identifier` Name of the role that the privilege was granted to
object_catalog `sql_identifier` Name of the database containing the object (always the current database)
object_schema `sql_identifier` Name of the schema containing the object, if applicable, else an empty string
object_name `sql_identifier` Name of the object
object_type `character_data` `COLLATION` or `DOMAIN` or `FOREIGN DATA WRAPPER` or `FOREIGN SERVER` or `SEQUENCE`
privilege_type `character_data` Always `USAGE`
is_grantable `yes_or_no` `YES` if the privilege is grantable, `NO` if not

## `user_defined_types`

The view `user_defined_types` currently contains all composite types defined in the current database. Only those types are shown that the current user has access to (by way of being the owner or having some privilege).

SQL knows about two kinds of user-defined types: structured types (also known as composite types in PostgreSQL) and distinct types (not implemented in PostgreSQL). To be future-proof, use the column `user_defined_type_category` to differentiate between these. Other user-defined types such as base types and enums, which are PostgreSQL extensions, are not shown here. For domains, see infoschema-domains instead.

## user_defined_types Columns

Column Type Description
user_defined_type_catalog `sql_identifier` Name of the database that contains the type (always the current database)
user_defined_type_schema `sql_identifier` Name of the schema that contains the type
user_defined_type_name `sql_identifier` Name of the type
user_defined_type_category `character_data` Currently always `STRUCTURED`
is_instantiable `yes_or_no` Applies to a feature not available in PostgreSQL
is_final `yes_or_no` Applies to a feature not available in PostgreSQL
ordering_form `character_data` Applies to a feature not available in PostgreSQL
ordering_category `character_data` Applies to a feature not available in PostgreSQL
ordering_routine_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
ordering_routine_schema `sql_identifier` Applies to a feature not available in PostgreSQL
ordering_routine_name `sql_identifier` Applies to a feature not available in PostgreSQL
reference_type `character_data` Applies to a feature not available in PostgreSQL
data_type `character_data` Applies to a feature not available in PostgreSQL
character_maximum_length `cardinal_number` Applies to a feature not available in PostgreSQL
character_octet_length `cardinal_number` Applies to a feature not available in PostgreSQL
character_set_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_schema `sql_identifier` Applies to a feature not available in PostgreSQL
character_set_name `sql_identifier` Applies to a feature not available in PostgreSQL
collation_catalog `sql_identifier` Applies to a feature not available in PostgreSQL
collation_schema `sql_identifier` Applies to a feature not available in PostgreSQL
collation_name `sql_identifier` Applies to a feature not available in PostgreSQL
numeric_precision `cardinal_number` Applies to a feature not available in PostgreSQL
numeric_precision_radix `cardinal_number` Applies to a feature not available in PostgreSQL
numeric_scale `cardinal_number` Applies to a feature not available in PostgreSQL
datetime_precision `cardinal_number` Applies to a feature not available in PostgreSQL
interval_type `character_data` Applies to a feature not available in PostgreSQL
interval_precision `cardinal_number` Applies to a feature not available in PostgreSQL
source_dtd_identifier `sql_identifier` Applies to a feature not available in PostgreSQL
ref_dtd_identifier `sql_identifier` Applies to a feature not available in PostgreSQL

## `user_mapping_options`

The view `user_mapping_options` contains all the options defined for user mappings in the current database. Only those user mappings are shown where the current user has access to the corresponding foreign server (by way of being the owner or having some privilege).

## user_mapping_options Columns

Column Type Description
authorization_identifier `sql_identifier` Name of the user being mapped, or `PUBLIC` if the mapping is public
foreign_server_catalog `sql_identifier` Name of the database that the foreign server used by this mapping is defined in (always the current database)
foreign_server_name `sql_identifier` Name of the foreign server used by this mapping
option_name `sql_identifier` Name of an option
option_value `character_data` Value of the option. This column will show as null unless the current user is the user being mapped, or the mapping is for `PUBLIC` and the current user is the server owner, or the current user is a superuser. The intent is to protect password information stored as user mapping option.

## `user_mappings`

The view `user_mappings` contains all user mappings defined in the current database. Only those user mappings are shown where the current user has access to the corresponding foreign server (by way of being the owner or having some privilege).

## user_mappings Columns

Column Type Description
authorization_identifier `sql_identifier` Name of the user being mapped, or `PUBLIC` if the mapping is public
foreign_server_catalog `sql_identifier` Name of the database that the foreign server used by this mapping is defined in (always the current database)
foreign_server_name `sql_identifier` Name of the foreign server used by this mapping

## `view_column_usage`

The view `view_column_usage` identifies all columns that are used in the query expression of a view (the `SELECT` statement that defines the view). A column is only included if the table that contains the column is owned by a currently enabled role.

Columns of system tables are not included. This should be fixed sometime.

## view_column_usage Columns

Column Type Description
view_catalog `sql_identifier` Name of the database that contains the view (always the current database)
view_schema `sql_identifier` Name of the schema that contains the view
view_name `sql_identifier` Name of the view
table_catalog `sql_identifier` Name of the database that contains the table that contains the column that is used by the view (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that contains the column that is used by the view
table_name `sql_identifier` Name of the table that contains the column that is used by the view
column_name `sql_identifier` Name of the column that is used by the view

## `view_routine_usage`

The view `view_routine_usage` identifies all routines (functions and procedures) that are used in the query expression of a view (the `SELECT` statement that defines the view). A routine is only included if that routine is owned by a currently enabled role.

## view_routine_usage Columns

Column Type Description
table_catalog `sql_identifier` Name of the database containing the view (always the current database)
table_schema `sql_identifier` Name of the schema containing the view
table_name `sql_identifier` Name of the view
specific_catalog `sql_identifier` Name of the database containing the function (always the current database)
specific_schema `sql_identifier` Name of the schema containing the function
specific_name `sql_identifier` The specific name of the function. See infoschema-routines for more information.

## `view_table_usage`

The view `view_table_usage` identifies all tables that are used in the query expression of a view (the `SELECT` statement that defines the view). A table is only included if that table is owned by a currently enabled role.

System tables are not included. This should be fixed sometime.

## view_table_usage Columns

Column Type Description
view_catalog `sql_identifier` Name of the database that contains the view (always the current database)
view_schema `sql_identifier` Name of the schema that contains the view
view_name `sql_identifier` Name of the view
table_catalog `sql_identifier` Name of the database that contains the table that is used by the view (always the current database)
table_schema `sql_identifier` Name of the schema that contains the table that is used by the view
table_name `sql_identifier` Name of the table that is used by the view

## `views`

The view `views` contains all views defined in the current database. Only those views are shown that the current user has access to (by way of being the owner or having some privilege).

## views Columns

Column Type Description
table_catalog `sql_identifier` Name of the database that contains the view (always the current database)
table_schema `sql_identifier` Name of the schema that contains the view
table_name `sql_identifier` Name of the view
view_definition `character_data` Query expression defining the view (null if the view is not owned by a currently enabled role)
check_option `character_data` `CASCADED` or `LOCAL` if the view has a `CHECK OPTION` defined on it, `NONE` if not
is_updatable `yes_or_no` `YES` if the view is updatable (allows `UPDATE` and `DELETE`), `NO` if not
is_insertable_into `yes_or_no` `YES` if the view is insertable into (allows `INSERT`), `NO` if not
is_trigger_updatable `yes_or_no` `YES` if the view has an `INSTEAD OF` `UPDATE` trigger defined on it, `NO` if not
is_trigger_deletable `yes_or_no` `YES` if the view has an `INSTEAD OF` `DELETE` trigger defined on it, `NO` if not
is_trigger_insertable_into `yes_or_no` `YES` if the view has an `INSTEAD OF` `INSERT` trigger defined on it, `NO` if not