How to Create Trigger in SQL
In this article I am going to explain how to create a trigger in SQL
Introduction
Triggers in SQL are a special type of procedure that are executed, fired or invoked automatically in response to an action query are executed on a view or table. We can set trigger on insertion, deletion and updating or combination of these operation.
There are three type of trigger in SQL.
- AFTER Trigger
- INSTEAD OF Trigger
- FOR Trigger
A Statement that create vendors table
create table vendors
(
vendorid int,
vendorname varchar(15),
vendorcity varchar(15),
vendorstate varchar(15)
)
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Statements that insert data in vendors table
insert into vendors values (20,'vipendra','noida','up')
insert into vendors values (21,'deepak','lucknow','up')
insert into vendors values (22,'rahul','kanpur','up')
insert into vendors values (23,'malay','delhi','delhi')
insert into vendors values (24,'mayank','noida','up')
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A Statement that is used to fetch data from vendors table
A Statement that is used to create a trigger
create trigger ven_trig
on vendors
after insert,update
as
update vendor
set vendorstate = upper(vendorstate)
where vendorid IN (select vendorid from inserted)
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