28.3.41 The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table (original) (raw)

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28.3.41 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 beUNIQUE, PRIMARY KEY,FOREIGN KEY or CHECK. This is a CHAR (notENUM) column.
  The UNIQUE and PRIMARY KEY information is about the same as what you get from the Key_name column in the output fromSHOW INDEX when theNon_unique column is 0.
• ENFORCED
  For CHECK constraints, the value isYES or NO to indicate whether the constraint is enforced. For other constraints, the value is always YES.