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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.
26 wrz 2009 · ON UPDATE CASCADE: SQL Server updates the corresponding rows in the child table when the rows in the parent table are updated. ON UPDATE SET NULL: SQL Server sets the rows in the child table to NULL when the corresponding row in the parent table is updated. Note that the foreign key columns must be nullable for this action to execute.
30 gru 2023 · The cascading referential integrity constraints in SQL servers are the foreign key constraints that tell SQL servers to perform certain actions whenever a user attempts to delete or update a primary key to which an existing foreign key points.
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.
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.
This article by scaler topics discusses the use of cascade while writing SQL queries and how to use cascade in MySQL and while using ON DELETE query.
12 lip 2013 · Use the ON DELETE CASCADE option if you want rows deleted in the child table when corresponding rows are deleted in the parent table. If you do not specify cascading deletes, the default behavior of the database server prevents you from deleting data in a table if other tables reference it.
