33.21. 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 33-19. key_column_usage Columns

NameData TypeDescription
constraint_catalogsql_identifierName of the database that contains the constraint (always the current database)
constraint_schemasql_identifierName of the schema that contains the constraint
constraint_namesql_identifierName of the constraint
table_catalogsql_identifier Name of the database that contains the table that contains the column that is restricted by this constraint (always the current database)
table_schemasql_identifier Name of the schema that contains the table that contains the column that is restricted by this constraint
table_namesql_identifier Name of the table that contains the column that is restricted by this constraint
column_namesql_identifier Name of the column that is restricted by this constraint
ordinal_positioncardinal_number Ordinal position of the column within the constraint key (count starts at 1)
position_in_unique_constraintcardinal_number For a foreign-key constraint, ordinal position of the referenced column within its unique constraint (count starts at 1); otherwise null