The issue about SQL statements that use triggers to delete tables

In the case of sqlserver, you can write a database-based trigger in which you can get the name of the table to be operated on, and sqlserver prohibits the user from deleting the specified table.

If in doubt, communicate in a timely manner!

This can be controlled by setting the user's operation permissions on the table.

create trigger t1 on reader instead of delete as

delete borrowing where reader number = (select reader number from deleted).

create trigger a_del

on [reader] for delete

as--set nocount on

delete e

from [Reader] e

inner join deleted [borrowing] on e.[Reader Number] = [Borrowing].[Reader Number].

Needless to say, it's just what kind of mechanism to use to implement it.

1. The trigger is only executed when the data is updated;

2. However, if you delete data, it is generally a scheduled job;

This is not a facilitator, you have to use a scheduler and let it run automatically every day.

This type of statement is available in later SQL versions.

create trigger trigger name.

on database

for drop_tableas

This trigger can be written like this, when someone deletes the data in table A, just execute a statement that will report an error.

No value was assigned to @plane seat.

in storage.

while.

Insert "select

plane_seat

plane_seat

frominserted”

***table a***

create table [dbo].[test_a](

id_a] [nchar](10) null,col1] [nchar](10) null,col2] [nchar](10) null,col3] [nchar](10) null

on [primary]

**table b***

create table [dbo].[test_b](

id_b] [nchar](10) null,col1] [nchar](10) null,col2] [nchar](10) null,col3] [nchar](10) null

on [primary]

**create trigger***

create trigger [dbo].[tri_test]

on [dbo].[test_a]

after delete

asdelete from test_b where id_b in (select id_a from deleted)

The ID of table A corresponds to the ID of table B

When you delete data in table A, the IDs associated with table B are also deleted.

In addition, foreign keys can achieve the same effect, and if the logic is relatively simple, foreign keys can be used.

Let the two table associated fields be:

The id** is as follows:

create trigger trnameon The name of the source table.

for delete

asdelete from destination table name where exists(select 1 from deleted where destination table name. id)

It's okay to write a trigger.,How to write it, you just look at the help of SQL.,I didn't give anything.,I can't write it to you.。

What do you need to ask?