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 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.