help me with this error

Question

This error appears when trying to cascade the relationship between a primary key and a foreign key

"

'Employees' table saved successfully

'PC_details' table

• Unable to create relationship 'FK_PC_details_Employees'.

Introducing FOREIGN KEY constraint 'FK_PC_details_Employees' on table 'PC_details' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

Could not create constraint or index. See previous errors.

"

Answer 1

Hi @medooouni1980

How about using ON DELETE SET NULL. The FK will be set to NULL rather than causing a cascading delete. Or you could use triggers to implement such logic.

Refer to this article for more details: Fix Error 1785 “Introducing FOREIGN KEY constraint … may cause cycles or multiple cascade paths” in SQL Server.

Best regards,

Cosmog

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Answer 2

Cascading foreign keys can certainly make things easier, but there are many restrictions with them. Typically, if you have two or more FK columns in a table that refers to the same parent table, you can only have one if them as cascading, and the remaining needs to be NO ACTION.

I should point out that there is nothing wrong with having multiple FK columns referring to the same table - that's a quite normal thing to do.