36.32. 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.

Table 36.30. key_column_usage Columns

Name	Data 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