This technique is very useful, handy and save you time for handling deletion of records from your code, say both from your header table and detail table. It also checks integrity, meaning, nothing left unwanted records for both tables if records is removed.
To set up cascading deletes in MySQL, so that when a record in the parent table (myheader
) is deleted, all related records in the child table (mydetail
) are also automatically deleted, you can use foreign key constraints with the ON DELETE CASCADE
option. Here’s how you can do it:
This SQL statement adds a foreign key constraint to the mydetail
table, referencing the id
column in the myheader
table. The ON DELETE CASCADE
option specifies that when a record in myheader
is deleted, all corresponding records in mydetail
with matching header_id
values should also be deleted automatically.
Make sure that both the myheader
and mydetail
tables are using the InnoDB storage engine, as foreign key constraints with cascading actions are only supported by InnoDB.
Note: Before adding foreign key constraints with cascading actions, make sure to back up your data, as cascading deletes can lead to unintended data loss if not used carefully.
If you’re using phpMyAdmin, you can add this foreign key constraint by following these steps:
mydetail
table.header_id
that references the myheader
table.myheader
and id
respectively).With this foreign key constraint in place with cascading delete, when a record is deleted from myheader
, all related records in mydetail
will be automatically deleted.
Do you want to add some thoughts?