使用级联删除约束时获取已删除记录的计数

Question

When using ON DELETE CASCADE constraint and deleting a "master" record is there a way to get the count of "child" records deleted?

For example using these table:

CREATE TABLE Master ( ID INT PRIMARY KEY (ID))
GO

CREATE TABLE Child ( ID INT, MasterID INT)
GO

ALTER TABLE Child ADD CONSTRAINT FK_Child_Master FOREIGN KEY(MasterID)
REFERENCES Master (ID)
ON DELETE CASCADE
GO

INSERT INTO Master (ID) VALUES (1);

INSERT INTO Child ( ID, MasterID) VALUES (1,1),(2,1),(3,1),(4,1),(5,1);

Now if I delete the master record like this:

DELETE FROM Master WHERE ID = 1;

SELECT @@ROWCOUNT;

The 5 rows in the Child table and the 1 row in the Master table are all deleted but the result is 1. It only counts the records deleted from the master table.

Is there a way to capture the number of rows deleted from the child table or do I need delete from the child table first, get the count, then delete from the master?

Answer 1

Yes you can use a stored procedure to do this like

create procedure spDeleteRecords
@id int
begin
    select count(*) from child_table where id=@id
    delete from parent_table where id=@id
end