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MySQL 5.6 Reference Manual  /  INFORMATION_SCHEMA Tables  /  The INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS Table

21.18 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.