The key_column_usage view provides information about columns restricted by key constraints.
| Column name | Data type | Description |
|---|---|---|
constraint_catalog |
sql_identifier |
The name of the current database containing the constraint. |
constraint_schema |
sql_identifier |
The name of the schema containing the constraint. |
constraint_name |
sql_identifier |
The name of the constraint. |
table_catalog |
sql_identifier |
The name of the current database holding the table that contains the column restricted by this constraint. |
table_schema |
sql_identifier |
The name of the schema holding the table that contains the column restricted by this constraint. |
table_name |
sql_identifier |
The name of the table holding the column restricted by this constraint. |
column_name |
sql_identifier |
The name of the column restricted by this constraint. |
ordinal_position |
cardinal_number |
The ordinal position of the column within the constraint key. The count starts at 1. |
position_in_unique_constraint |
cardinal_number |
For a foreign-key constraint, the ordinal position of the referenced column within its unique constraint. The count starts at 1.NULL – The constraint is not a foreign key. |