TABLE_CONSTRAINTS
The TABLE_CONSTRAINTS table describes which tables have constraints.
sql
DESC INFORMATION_SCHEMA.table_constraints;DESC INFORMATION_SCHEMA.table_constraints;sql
+--------------------+--------+------+------+---------+---------------+
| Column | Type | Key | Null | Default | Semantic Type |
+--------------------+--------+------+------+---------+---------------+
| constraint_catalog | String | | NO | | FIELD |
| constraint_schema | String | | NO | | FIELD |
| constraint_name | String | | NO | | FIELD |
| table_schema | String | | NO | | FIELD |
| table_name | String | | NO | | FIELD |
| constraint_type | String | | NO | | FIELD |
| enforced | String | | NO | | FIELD |
+--------------------+--------+------+------+---------+---------------++--------------------+--------+------+------+---------+---------------+
| Column | Type | Key | Null | Default | Semantic Type |
+--------------------+--------+------+------+---------+---------------+
| constraint_catalog | String | | NO | | FIELD |
| constraint_schema | String | | NO | | FIELD |
| constraint_name | String | | NO | | FIELD |
| table_schema | String | | NO | | FIELD |
| table_name | String | | NO | | FIELD |
| constraint_type | String | | NO | | FIELD |
| enforced | String | | NO | | FIELD |
+--------------------+--------+------+------+---------+---------------+The columns in the table:
CONSTRAINT_CATALOG: The name of the catalog to which the constraint belongs. This value is alwaysdef.CONSTRAINT_SCHEMA: The name of the database to which the constraint belongs.CONSTRAINT_NAME: The name of the constraint,TIME INDEXorPRIMARY.TABLE_NAME: The name of the table.CONSTRAINT_TYPE: The type of the constraint. The value can beTIME INDEXorPRIMARY KEY. TheTIME INDEXandPRIMARY KEYinformation is similar to the execution result of theSHOW INDEXstatement.enforced: Doesn't supportCHECKconstraints, the value is alwaysYES.
sql
select * from INFORMATION_SCHEMA.table_constraints WHERE table_name = 'monitor'\G;select * from INFORMATION_SCHEMA.table_constraints WHERE table_name = 'monitor'\G;The output:
sql
*************************** 1. row ***************************
constraint_catalog: def
constraint_schema: public
constraint_name: TIME INDEX
table_schema: public
table_name: monitor
constraint_type: TIME INDEX
enforced: YES
*************************** 2. row ***************************
constraint_catalog: def
constraint_schema: public
constraint_name: PRIMARY
table_schema: public
table_name: monitor
constraint_type: PRIMARY KEY
enforced: YES*************************** 1. row ***************************
constraint_catalog: def
constraint_schema: public
constraint_name: TIME INDEX
table_schema: public
table_name: monitor
constraint_type: TIME INDEX
enforced: YES
*************************** 2. row ***************************
constraint_catalog: def
constraint_schema: public
constraint_name: PRIMARY
table_schema: public
table_name: monitor
constraint_type: PRIMARY KEY
enforced: YES