http://vadivel.blogspot.com/2011/09/does-clustered-index-physically-orders.html

I would like to learn how logs can be used to roll back delete ,update etc in table .

thanks and regards

Can you please help me to log in to this team?

1,For a normal update statement, is it possible to use logs to roll back, if yes how is it done, can you please explain with examples.

2, how do we use log files to restore backups. Please explain with examples.

Thanks in advance

I assume when we say a Multi Column Sub Query we are talking about an alias table. Let’s see this with an example.

– First Tables store static data about employee details
Create Table #Example1 ( Eid int , Ename varchar(10))
insert into #Example1 values ( 1, ‘Mr W’)
insert into #Example1 values ( 2, ‘Mr X’)
insert into #Example1 values ( 3, ‘Mr Y’)
insert into #Example1 values ( 4, ‘Mr Z’)

–Second Table stores sales data, how much sales each employee made each month..
Create Table #Example2 ( Eid int , Sales_Made int , date datetime )
insert into #Example2 values ( 1, 10 , ’06/30/2006′)
insert into #Example2 values ( 1, 15 , ’07/30/2009′)
insert into #Example2 values ( 1, 20 , ’08/30/2008′)
insert into #Example2 values ( 1, 30 , ’07/30/2009′)

insert into #Example2 values ( 2, 15 , ’06/30/2006′)
insert into #Example2 values ( 2, 14 , ’09/30/2007′)
insert into #Example2 values ( 2, 23 , ’07/30/2009′)
insert into #Example2 values ( 2, 32 , ’07/30/2009′)

insert into #Example2 values ( 3, 12 , ’07/30/2009′)
insert into #Example2 values ( 3, 13 , ’09/30/2007′)
insert into #Example2 values ( 3, 24 , ’08/30/2008′)
insert into #Example2 values ( 3, 32 , ’07/30/2009′)

insert into #Example2 values ( 4, 13 , ’06/30/2006′)
insert into #Example2 values ( 4, 15 , ’07/30/2009′)
insert into #Example2 values ( 4, 25 , ’08/30/2008′)
insert into #Example2 values ( 4, 34 , ’07/30/2009′)

– You want to see total sales made by each employee in last month.
– There could be many other ways to solve this, it is only to show you multi column subquery I opted this route.
Select A.Eid
,A.Ename
,B.Total_Sales
,B.Last_Month
FROM #Example1 A JOIN
— Start of Multi Column Sub Query
(
select Eid
,SUM(Sales_Made) Total_Sales
,Max (Date) Last_Month
from #Example2
group by Eid
) — End of Multi Column Sub Query
B ON A.Eid = B.Eid

drop table #Example1 , #Example2

~ IM.

Can you give an example of a Multi Column Sub Query??

Thanks

Multiple column sub-query, where the sub-query returns multiple columns

can give an example for this

Thanks

Having is applied on the result set

Thanks

You are correct.

If you use TRANSACTION you can roll back TRUNCATE.

If you do not use TRANSACTION you can not use logs to roll back TRUNCATE.

DELETE can be rolled back in either condition.

I have in depth discussed this issue. If you can click on (Read More Here) link there is discussion about the same issue.

http://blog.sqlauthority.com/2007/12/26/sql-server-truncate-cant-be-rolled-back-using-log-files-after-transaction-session-is-closed/

Again, your comment is first comment in this article and readers will be not confused after reading them.

Kind Regards,
Pinal Dave ( http://blog.sqlauthority.com )

This is regarding truncate and delete….

I dont know if you cannot rollback truncate by default… but if you use begin tran with truncate statement then Yes you can rollback.

Please clarify,,, I can be wrong as well…

This is my example :

create table example1 ( eid int )
go
insert into example1 values ( 1)
insert into example1 values ( 2)
insert into example1 values ( 3)
go
select * from example1
go
begin tran T1
truncate table example1
go
select * from example1
go
rollback tran T1
go
begin Tran T2
delete from example1 where eid = 1
select * from example1
go
rollback tran T2
go
select * from example1
go

Thanks.
Imran.