4.20 The INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS Table

The REFERENTIAL_CONSTRAINTS table provides information about foreign keys.

The REFERENTIAL_CONSTRAINTS table has these columns:

• CONSTRAINT_CATALOG

  The name of the catalog to which the constraint belongs. This value is always def.

• CONSTRAINT_SCHEMA

  The name of the schema (database) to which the constraint belongs.

• CONSTRAINT_NAME

  The name of the constraint.

• UNIQUE_CONSTRAINT_CATALOG

  The name of the catalog containing the unique constraint that the constraint references. This value is always def.

• UNIQUE_CONSTRAINT_SCHEMA

  The name of the schema (database) containing the unique constraint that the constraint references.

• UNIQUE_CONSTRAINT_NAME

  The name of the unique constraint that the constraint references.

• MATCH_OPTION

  The value of the constraint MATCH attribute. The only valid value at this time is NONE.

• UPDATE_RULE

  The value of the constraint ON UPDATE attribute. The possible values are CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION.

• DELETE_RULE

  The value of the constraint ON DELETE attribute. The possible values are CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION.

• TABLE_NAME

  The name of the table. This value is the same as in the TABLE_CONSTRAINTS table.

• REFERENCED_TABLE_NAME

  The name of the table referenced by the constraint.