Find fremmednøgleoplysninger ved hjælp af Perl/DBI/MySQL/InnoDB

Det ser ud til, at det muligvis ikke understøttes af mysql-driveren endnu. Ved at foretage et hurtigt tjek gennem debug, ser det ud til, at følgende sql-sætning bliver indtastet:

SELECT NULL AS PKTABLE_CAT,
   A.REFERENCED_TABLE_SCHEMA AS PKTABLE_SCHEM,
   A.REFERENCED_TABLE_NAME AS PKTABLE_NAME,
   A.REFERENCED_COLUMN_NAME AS PKCOLUMN_NAME,
   A.TABLE_CATALOG AS FKTABLE_CAT,
   A.TABLE_SCHEMA AS FKTABLE_SCHEM,
   A.TABLE_NAME AS FKTABLE_NAME,
   A.COLUMN_NAME AS FKCOLUMN_NAME,
   A.ORDINAL_POSITION AS KEY_SEQ,
   NULL AS UPDATE_RULE,
   NULL AS DELETE_RULE,
   A.CONSTRAINT_NAME AS FK_NAME,
   NULL AS PK_NAME,
   NULL AS DEFERABILITY,
   NULL AS UNIQUE_OR_PRIMARY
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE A,
   INFORMATION_SCHEMA.TABLE_CONSTRAINTS B
WHERE A.TABLE_SCHEMA = B.TABLE_SCHEMA AND A.TABLE_NAME = B.TABLE_NAME
   AND A.CONSTRAINT_NAME = B.CONSTRAINT_NAME AND B.CONSTRAINT_TYPE IS NOT NULL
   AND A.TABLE_NAME = ? ORDER BY A.TABLE_SCHEMA, A.TABLE_NAME, A.ORDINAL_POSITION

Bemærk, at kolonnerne UPDATE_RULE og DELETE_RULE begge er sat til NULL.