How to delete a table with a foreign key?
Set the FOREIGN_KEY_CHECKS before and after your delete SQL statements. SET FOREIGN_KEY_CHECKS = 0; DELETE FROM table WHERE DELETE FROM table WHERE DELETE FROM table WHERE SET FOREIGN_KEY_CHECKS = 1;
How to remove a FOREIGN KEY constraint in MySQL?
This solution temporarily disables checking the restraints and then re-enables them. Read the documentation for more. Be sure to delete foreign key restraints and fields in tables depending on bericht, otherwise you might leave your database in a broken state.
Is there way to prevent delete s in MySQL?
Preventing DELETE s is something you want in such cases. Or, even better, change the foreign key once, so it does the deletion automatically (cascading): To expand on the accepted answer, you have to specify the constraint name after DROP FOREIGN KEY
When does a FOREIGN KEY constraint fail in InnoDB?
The #1217 error happens when other tables has foreign key constraints to the table you are trying to delete and you are using the InnoDB database engine. This solution temporarily disables checking the restraints and then re-enables them. Read the documentation for more.
When to delete data from a table with FKS?
There are generally two scenarios when deleting data from tables with FKs, one is to delete all of the data and the other is to delete a few records. Of course, for both scenarios we need to delete from the tables in the right order.
Do you need to change schema for foreign key delete?
If you wish the delete to be automatic, you need to change your schema so that the foreign key constraint is ON DELETE CASCADE. For more information, see the MSDN page on Cascading Referential Integrity Constraints.
Do you have to delete all data from Table1?
If I want to delete some data or all data from Table1 and the FKs are not configured as cascading constraints on delete, then if I need to delete from Table1 I have to delete from the leaf level tables first which can get tricky to figure out.