20.12. The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table

20.12. The `INFORMATION_SCHEMA TABLE_CONSTRAINTS` Table

The TABLE_CONSTRAINTS table describes which tables have constraints.

Notes:

The CONSTRAINT_TYPE value can be UNIQUE, PRIMARY KEY, or FOREIGN KEY.
The UNIQUE and PRIMARY KEY information is about the same as what you get from the Key_name field in the output from SHOW INDEX when the Non_unique field is 0.
The CONSTRAINT_TYPE column can contain one of these values: UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK. This is a CHAR (not ENUM) column. The CHECK value is not available until we support CHECK.