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.
3 lip 2019 · In this article, we will review on DELETE CASCADE AND UPDATE CASCADE rules in SQL Server foreign key with different examples. DELETE CASCADE : When we create a foreign key using this option, it deletes the referencing rows in the child table when the referenced row is deleted in the parent table which has a primary key.
1 sie 2012 · This tip will look at the DELETE CASCADE option when creating foreign key constraints and how it helps keep the referential integrity of your database intact.
Using the DELETE CASCADE option in your foreign key constraint definitions means better performance and less code when removing records from tables that have a parent-child relationship defined.
Use cascade delete where you would want the record with the FK to be removed if its referring PK record was removed. In other words, where the record is meaningless without the referencing record. I find cascade delete useful to ensure that dead references are removed by default rather than cause null exceptions.
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.
In this tip we look at a SQL Server script you can use to see the impact of deleting a record from a table has on other tables that have foreign key references to table. Menu Join
