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.