MySQL 5.1 Reference Manual  /  INFORMATION_SCHEMA Tables  /  The INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS Table

20.15 The INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS Table

The REFERENTIAL_CONSTRAINTS table provides information about foreign keys.

INFORMATION_SCHEMA NameSHOW NameRemarks
CONSTRAINT_CATALOG NULL
CONSTRAINT_SCHEMA
CONSTRAINT_NAME
UNIQUE_CONSTRAINT_CATALOG NULL
UNIQUE_CONSTRAINT_SCHEMA
UNIQUE_CONSTRAINT_NAME
MATCH_OPTION
UPDATE_RULE
DELETE_RULE
TABLE_NAME
REFERENCED_TABLE_NAME

Notes:

  • The REFERENTIAL_CONSTRAINTS table was added in MySQL 5.1.10. The REFERENCED_TABLE_NAME column was added in MySQL 5.1.16.

  • TABLE_NAME has the same value as TABLE_NAME in INFORMATION_SCHEMA.TABLE_CONSTRAINTS.

  • CONSTRAINT_SCHEMA and CONSTRAINT_NAME identify the foreign key.

  • UNIQUE_CONSTRAINT_SCHEMA, UNIQUE_CONSTRAINT_NAME, and REFERENCED_TABLE_NAME identify the referenced key. (Note: Before MySQL 5.1.16, UNIQUE_CONSTRAINT_NAME incorrectly named the referenced table, not the constraint.)

  • The only valid value at this time for MATCH_OPTION is NONE.

  • The possible values for UPDATE_RULE or DELETE_RULE are CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION.


User Comments
  Posted by Hugo Silva on November 27, 2009
on windows, the values of referenced_table_name column are always in lowercase, even if you set lower_case_table_names = 0.
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