SQL Server Triggers

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Meganadha Reddy K.Technical Trainer | NetCom Learning

www.NetComLearning.com

Agenda

• SQL Server Objects

• SQL Server Constraints

• Triggers

• Types of Triggers

• Demos

• Q & A

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

SQL Server Objects

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Tables

Views Columns

Constraints

Functions

Stored Procedures

Triggers

Joins

SysTables

Logins

indexes

Transactions

Backups

TABLES

• Rows and Columns

• A database will have at least one table.

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

EmpId EmpName EmpDept

1 Meg IT

2 Harry Sales

3 Llew Admin

Constraints

• Primary Key : Unique way to differentiate each row of a table.

• Unique Key : Same as above but allows null value only once

• Not Null

• Default

• Check

SysTables

In Software Projects we frequently use below:

Sys.Columns

Sys.Objects

SysComments

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Additional Objects

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

• Stored Procedures

• Functions

• Views

• Triggers

• Cursors

• Joins : To retrieve data from more than one table

TRIGGERS

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Triggers

Instead of TriggersAfter Triggers

Insert Update Delete Insert Update Delete

Demo : Trigger (1 of 3)

• Lets take table : Employee

CREATE TABLE Employee

(

Emp_ID INT Identity,

Emp_name Varchar(100),

Emp_Sal Decimal (10,2)

)

INSERT INTO Employee VALUES (‘James',1200);

INSERT INTO Employee VALUES (‘Nick',1400);

INSERT INTO Employee VALUES (‘Raj',1000);

INSERT INTO Employee VALUES (‘Ravi',1100);

INSERT INTO Employee VALUES (‘Llew',1500);

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Demo : Trigger (2 of 3)

CREATE TABLE Employee_Audit

(

Emp_ID int,

Emp_name varchar(100),

Emp_Sal decimal (10,2),

Audit_Action varchar(100),

Audit_Timestamp datetime

)

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Demo : Trigger (3 of 3)

CREATE TRIGGER trgAfterInsert ON [dbo].[Employee] FOR INSERT

AS

declare @empid int;

declare @empname varchar(100);

declare @empsal decimal(10,2);

declare @audit_action varchar(100);

select @empid=i.Emp_ID from inserted i;

select @empname=i.Emp_Name from inserted i;

select @empsal=i.Emp_Sal from inserted i;

set @audit_action='Inserted Record -- After Insert Trigger.';

insert into Employee_Audit

(Emp_ID,Emp_Name,Emp_Sal,Audit_Action,Audit_Timestamp)

values(@empid,@empname,@empsal,@audit_action,getdate());

PRINT 'AFTER INSERT trigger fired.'

GO

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Triggers

More Demos

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/

Q & A

?

© Meganadha Reddy K., 2015 http://www.netcomlearning.com/