MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
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.
TABLE_SCHEMA
The name of the schema (database) to which the table belongs.
TABLE_NAME
The name of the table.
The 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
CHECK
value is not available until MySQL
supports CHECK
.
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
.