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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.
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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.
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.
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.
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.
The MySQL ON DELETE CASCADE constraint ensures that when a row in the parent table is deleted, all related rows in the child table are automatically deleted as well. This constraint helps maintain referential integrity between two tables that are connected through a foreign key relationship.
12 sty 2022 · Using ON DELETE CASCADE, all the related records in the child table get automatically deleted when the parent table data is deleted. The ON DELETE CASCADE helps you avoid writing nested queries for deleting the child table data respective to parent table data.
