Search results
To add "Cascade delete" to an existing foreign key in SQL Server Management Studio: First, select your Foreign Key, and open it's "DROP and Create To.." in a new Query window. Then, just add ON DELETE CASCADE to the ADD CONSTRAINT command: And hit the "Execute" button to run this query.
8 lut 2021 · ON DELETE CASCADE constraint is used in MySQL to delete the rows from the child table automatically, when the rows from the parent table are deleted. For example when a student registers in an online learning platform, then all the details of the student are recorded with their unique number/id.
30 gru 2023 · The ON DELETE CASCADE option in PL/SQL is used to automatically delete rows from a child table when the corresponding row in the parent table is deleted. This feature helps maintain referential integrity by ensuring that related records in child tables are removed in sync with changes in the parent table.
20 cze 2013 · ON DELETE CASCADE: if a row of the referenced table is deleted, then all matching rows in the referencing table are deleted. ON DELETE SET NULL : if a row of the referenced table is deleted, then all referencing columns in all matching rows of the referencing table to be set to null.
This tutorial shows you how to use MySQL ON DELETE CASCADE to automatically delete data from a child table when you delete data from the parent table.
First drop your foreign key and try your above command, put add constraint instead of modify constraint. Now this is the command: ALTER TABLE child_table_name ADD CONSTRAINT fk_name FOREIGN KEY (child_column_name) REFERENCES parent_table_name(parent_column_name) ON DELETE CASCADE;
16 sie 2023 · The ON DELETE CASCADE feature in SQL allows you to delete child rows when a parent row is deleted. Learn all about it in this guide.
