28.3.43 The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table

The TABLE_CONSTRAINTS table describes which tables have constraints.

The TABLE_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.

• TABLE_SCHEMA

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

• TABLE_NAME

  The name of the table.

• CONSTRAINT_TYPE

  The type of constraint. The value can be UNIQUE, PRIMARY KEY, FOREIGN KEY or CHECK. This is a CHAR (not ENUM) column.

  The UNIQUE and PRIMARY KEY information is about the same as what you get from the Key_name column in the output from SHOW INDEX when the Non_unique column is 0.

• ENFORCED

  For CHECK constraints, the value is YES or NO to indicate whether the constraint is enforced. For other constraints, the value is always YES.