The REFERENTIAL_CONSTRAINTS table
provides information about foreign keys.
INFORMATION_SCHEMA Name | SHOW Name | Remarks |
|---|---|---|
| CONSTRAINT_CATALOG | def | |
| CONSTRAINT_SCHEMA | ||
| CONSTRAINT_NAME | ||
| UNIQUE_CONSTRAINT_CATALOG | def | |
| UNIQUE_CONSTRAINT_SCHEMA | ||
| UNIQUE_CONSTRAINT_NAME | ||
| MATCH_OPTION | ||
| UPDATE_RULE | ||
| DELETE_RULE | ||
| TABLE_NAME | ||
| REFERENCED_TABLE_NAME |
Notes:
TABLE_NAMEhas the same value asTABLE_NAMEinINFORMATION_SCHEMA.TABLE_CONSTRAINTS.CONSTRAINT_SCHEMAandCONSTRAINT_NAMEidentify the foreign key.UNIQUE_CONSTRAINT_SCHEMA,UNIQUE_CONSTRAINT_NAME, andREFERENCED_TABLE_NAMEidentify the referenced key.The only valid value at this time for
MATCH_OPTIONisNONE.The possible values for
UPDATE_RULEorDELETE_RULEareCASCADE,SET NULL,SET DEFAULT,RESTRICT,NO ACTION.