If a foreign key was created without a name, MySql will give it a default one. For instance, for table 'Test' the foreign key will be named 'test_ibfk_1'. When I drop the foreign key locally by using this name it works like a charm but on the development server it fails with errno: 152.
I know this name is case sensitive but either lower or upper case the result is the same.
My question: Is it safe to rely on the default name to manipulate constraints (in MySql at least)?
Thanks in advance!
You need to know the name of foreign key. If it was created without name, then name will be autogenerated. You should get information about the foreign key.
Use one of these queries to get foreign key names -
SELECT constraint_name FROM information_schema.REFERENTIAL_CONSTRAINTS WHERE constraint_schema = <'db_name'> AND table_name = <'table_name'>; SELECT * FROM information_schema.KEY_COLUMN_USAGE WHERE constraint_schema = <'db_name'> AND table_name = <'table_name'> AND referenced_table_name IS NOT NULL;
ALTER TABLE <table_name> DROP INDEX <fk_name>; to drop foreign key.