Cascade deletion with triggers

This problem occurs when the table is deleted in cascade mode. An error occurs when a primary key information is deleted. Because there are foreign key information, a trigger is used to delete all the information.
 
<Span style = "font-family: Microsoft YaHei; font-size: 16px; color: # 6600cc;"> create trigger trigCategoryDelete (create trigger)
ON Category (ON which table to create)
After DELETE (trigger event)
AS
BEGIN
Delete news where caID = (select id from deleted) (some processing statements triggered by the trigger)
END
</Span>

However, after is after the delete operation, an error is returned. The delete operation is complete. How can I delete a foreign key.
Instead of replaces the delete statement:
 
<Span style = "font-family: Microsoft YaHei; font-size: 16px; color: # 6600cc;"> alter trigger [dbo]. [trigCategoryDelete]
ON [dbo]. [category]
Instead of DELETE
AS
BEGIN
Declare @ id int
Select @ id = id from deleted
-- Delete news
Delete news where caId = @ id
-- Delete a news category
Delete category where id = @ id
END </span>
In this way, the information in the foreign key can be deleted.
Cascade deletion of three tables
 
<Span style = "font-family: Microsoft YaHei; font-size: 16px; color: # 6600cc;"> alter trigger [dbo]. [trigCategoryDelete]
ON [dbo]. [category]
Instead of DELETE
AS
BEGIN
Declare @ caId int
Select @ caId = id from deleted
-- Delete comment
Delete comment where newsId = (select id from news where caId = @ caId)
-- Delete news
Delete news where caId = @ caId
-- Delete a news category
Delete category where id = @ caId
END </span>

 
In this case, an error will be reported, and the error will correspond to multiple comments in a piece of news. The solution is to change "=" to "in", so that all comments can be deleted.
Ps: as for the names of the logtail and tables in the front, we believe most people know that when the trigger is saved and then opened, the table information will be automatically completed.

Author: lixueru0819