referential_constraints

The referential_constraints view provides information about foreign keys. This view is read-only. All users have the read permission on this view.

**Table 1** information_schema.referential_constraints columns
Name	Type	Description
CONSTRAINT_CATALOG	varchar(512)	Name of the database to which the constraint belongs. The value is the database to which the constraint belongs. When lower_case_table_names is set to 0, the value of this column is case-sensitive. When lower_case_table_names is set to 1, the value of this column is case-insensitive.
CONSTRAINT_SCHEMA	varchar(64)	Name of the schema to which the constraint belongs. When lower_case_table_names is set to 0, the value of this column is case-sensitive. When lower_case_table_names is set to 1, the value of this column is case-insensitive.
CONSTRAINT_NAME	varchar(64)	Name of the constraint.
UNIQUE_CONSTRAINT_CATALOG	varchar(512)	Name of the catalog containing the UNIQUE constraint that the constraint references. The value is the database to which the UNIQUE constraint belongs. When lower_case_table_names is set to 0, the value of this column is case-sensitive. When lower_case_table_names is set to 1, the value of this column is case-insensitive.
UNIQUE_CONSTRAINT_SCHEMA	varchar(64)	Name of the schema containing the UNIQUE constraint that the constraint references. When lower_case_table_names is set to 0, the value of this column is case-sensitive. When lower_case_table_names is set to 1, the value of this column is case-insensitive.
UNIQUE_CONSTRAINT_NAME	varchar(64)	Name of the UNIQUE constraint that the constraint references.
MATCH_OPTION	varchar(64)	Value of the match constraint attribute.
UPDATE_RULE	varchar(64)	Value of the on update constraint attribute. The value is cascade, set null, set default, restrict, or no action.
DELETE_RULE	varchar(64)	Value of the on delete constraint attribute. The value is cascade, set null, set default, restrict, or no action.
TABLE_NAME	varchar(64)	Name of the table on which the constraint is defined. When lower_case_table_names is set to 0, the value of this column is case-sensitive. When lower_case_table_names is set to 1, the value of this column is case-insensitive.
REFERENCED_TABLE_NAME	varchar(64)	Name of the table referenced by the constraint. When lower_case_table_names is set to 0, the value of this column is case-sensitive. When lower_case_table_names is set to 1, the value of this column is case-insensitive.