columns

The columns view provides information about all table or view columns in the database.

Column name	Data type	Description
table_catalog	sql_identifier	The name of the current database containing the table.
table_schema	sql_identifier	The name of the schema containing the table.
table_name	sql_identifier	The name of the table.
column_name	sql_identifier	The name of the column.
ordinal_position	cardinal_number	The ordinal position of the table column. The count starts at 1.
column_default	character_data	The default expression of the column.
is_nullable	yes_or_no	Specifies whether the column is possibly nullable (YES) or not (NO).
data_type	character_data	The data type of the column. For built-in types, the type name is used. The possible values are: ARRAY – An array type. USER-DEFINED – A user-defined type. For domain-based columns, the value refers to the underlying type (the domain is identified in domain_name and related columns).
character_maximum_length	cardinal_number	The declared maximum length if data_type identifies a character or bit string type. NULL – All other types or if no maximum length is declared.
character_octet_length	cardinal_number	The maximum possible length, in octets, if data_type identifies a character type. NULL – All other types.
numeric_precision	cardinal_number	The declared or implicit precision of numeric types. NULL – All other data types.
numeric_precision_radix	cardinal_number	The base (2 or 10) in which numeric precision and scale are expressed. NULL – Non-numeric data types.
numeric_scale	cardinal_number	The scale (digits to the right of the decimal) of numeric data types. NULL – All other data types.
datetime_precision	cardinal_number	The fractional seconds precision of date/time/timestamp/interval types. NULL – All other data types.
interval_type	character_data	Specifies which interval fields are included in interval data types. For example, YEAR TO MONTH. NULL – A non-interval type.
interval_precision	cardinal_number	Applies to a feature that is not available in PostgreSQL.
character_set_catalog	sql_identifier	Applies to a feature that is not available in PostgreSQL.
character_set_schema	sql_identifier	Applies to a feature that is not available in PostgreSQL.
character_set_name	sql_identifier	Applies to a feature that is not available in PostgreSQL.
collation_catalog	sql_identifier	The name of the database containing the column’s collation, or NULL if default or not collatable.
collation_schema	sql_identifier	The name of the schema containing the column’s collation. NULL – Default or not collatable.
collation_name	sql_identifier	The name of the column’s collation. NULL – Default or not collatable.
domain_catalog	sql_identifier	The name of the database in which the domain is defined. Applies if the column uses a domain type. Otherwise, NULL.
domain_schema	sql_identifier	The name of the schema in which the domain is defined. Applies if the column uses a domain type. Otherwise, NULL.
domain_name	sql_identifier	The name of the domain. Applies if the column uses a domain type. Otherwise, NULL.
udt_catalog	sql_identifier	The name of the current database where the column’s underlying data type is defined.
udt_schema	sql_identifier	The name of the schema where the column’s underlying data type is defined.
udt_name	sql_identifier	The name of the column’s underlying data type.
scope_catalog	sql_identifier	Applies to a feature that is not available in PostgreSQL.
scope_schema	sql_identifier	Applies to a feature that is not available in PostgreSQL.
scope_name	sql_identifier	Applies to a feature that is not available in PostgreSQL.
maximum_cardinality	cardinal_number	The maximum cardinality of the array. Always NULL, because arrays in PostgreSQL have unlimited maximum cardinality.
dtd_identifier	sql_identifier	An identifier for the column’s data type descriptor, guaranteed to be unique in the table.
is_self_referencing	yes_or_no	Applies to a feature that is not available in PostgreSQL.
is_identity	yes_or_no	Specifies whether the column is an identity column (YES) or not (NO).
identity_generation	character_data	Specifies how an identity column generates a value. The possible values are: ALWAYS – The value is always generated by the system. BY DEFAULT – The system generates a value only when none is provided in an INSERT statement.
identity_start	character_data	The start value of the identity sequence. NULL – Not applicable.
identity_increment	character_data	The increment of the identity sequence. NULL – Not applicable.
identity_maximum	character_data	The maximum value of the identity sequence. NULL – Not applicable.
identity_minimum	character_data	The minimum value of the identity sequence. NULL – Not applicable.
identity_cycle	yes_or_no	Specifies whether the identity sequence cycles (YES) or not (NO). NULL – Not applicable.
is_generated	character_data	Specifies how the column value is generated. The possible values are: ALWAYS – The value is always generated by the system. NEVER – The value is not generated.
generation_expression	character_data	The generation expression for generated columns. NULL – Not applicable.
is_updatable	yes_or_no	Specifies whether the column is updatable (YES) or not (NO).