Click here to monitor SSC
SQLServerCentral is supported by Redgate
 
Log in  ::  Register  ::  Not logged in
 
 
 


Is this syntax guaranteed to continue working?


Is this syntax guaranteed to continue working?

Author
Message
Adi Cohn-120898
Adi Cohn-120898
SSCrazy
SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)

Group: General Forum Members
Points: 2222 Visits: 6076
Hi all

Pleas check out the code bellow:

declare @tbl table (i int)
declare @i int

insert into @tbl (i) values (1)

update @tbl
set @i = i, i = 2

select @i as varible, i from @tbl



This code stores the column's old value in a variable and then modifies the column's value. I know that code like that has been working for years, but I don't know if it is something that could be modified in the future. If an application has this kind of code, could it break with the next service pack or next SQL Server version or is this kind of code something that should always work?

Adi

--------------------------------------------------------------
To know how to ask questions and increase the chances of getting asnwers:
http://www.sqlservercentral.com/articles/Best+Practices/61537/

For better answers on performance questions, click on the following...
http://www.sqlservercentral.com/articles/SQLServerCentral/66909/
Koen Verbeeck
Koen Verbeeck
SSCoach
SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)

Group: General Forum Members
Points: 16441 Visits: 13202
This is known as the all-at-once concept in SQL Server.

All-At-Once Operations

This should continue to work in next versions of SQL Server.



How to post forum questions.
Need an answer? No, you need a question.
What’s the deal with Excel & SSIS?

Member of LinkedIn. My blog at SQLKover.

MCSA SQL Server 2012 - MCSE Business Intelligence
Eugene Elutin
Eugene Elutin
Hall of Fame
Hall of Fame (3K reputation)Hall of Fame (3K reputation)Hall of Fame (3K reputation)Hall of Fame (3K reputation)Hall of Fame (3K reputation)Hall of Fame (3K reputation)Hall of Fame (3K reputation)Hall of Fame (3K reputation)

Group: General Forum Members
Points: 3042 Visits: 5478
Nothing is certain but death and taxes


You should hope that it will work for ever.
Right now, there is nothing in MS BoL which suggests that they might change this bahaviour:
http://msdn.microsoft.com/en-us//library/ms177523.aspx

_____________________________________________
"The only true wisdom is in knowing you know nothing"
"O skol'ko nam otkrytiy chudnyh prevnosit microsofta duh!":-D
(So many miracle inventions provided by MS to us...)

How to post your question to get the best and quick help
Adi Cohn-120898
Adi Cohn-120898
SSCrazy
SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)

Group: General Forum Members
Points: 2222 Visits: 6076
Thank you for your replies. I appreciate your fast help.

Adi

--------------------------------------------------------------
To know how to ask questions and increase the chances of getting asnwers:
http://www.sqlservercentral.com/articles/Best+Practices/61537/

For better answers on performance questions, click on the following...
http://www.sqlservercentral.com/articles/SQLServerCentral/66909/
Jeff Moden
Jeff Moden
SSC-Forever
SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)

Group: General Forum Members
Points: 44994 Visits: 39880
Adi Cohn-120898 (7/8/2013)
Hi all

Pleas check out the code bellow:

declare @tbl table (i int)
declare @i int

insert into @tbl (i) values (1)

update @tbl
set @i = i, i = 2

select @i as varible, i from @tbl



This code stores the column's old value in a variable and then modifies the column's value. I know that code like that has been working for years, but I don't know if it is something that could be modified in the future. If an application has this kind of code, could it break with the next service pack or next SQL Server version or is this kind of code something that should always work?

Adi


It sounds like you're scoping out a project, Adi. What do you actually need this for? I ask because what you've posted makes up the "guts" of what has become endearingly known as the "Quirky Update" which, BTW, can also take the form of SET @variable = column = expression when used with some care.

--Jeff Moden

RBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
     Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
Although they tell us that they want it real bad, our primary goal is to ensure that we dont actually give it to them that way.
Although change is inevitable, change for the better is not.
Just because you can do something in PowerShell, doesnt mean you should. Wink

Helpful Links:
How to post code problems
How to post performance problems
Forum FAQs
Adi Cohn-120898
Adi Cohn-120898
SSCrazy
SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)

Group: General Forum Members
Points: 2222 Visits: 6076
Jeff – Sorry for disappearing, but for some reason I missed your response. What I wanted to do was very simple. I was working on improving performance on a stored procedure. One of the changes that I've made was to make fewer data access statements. In the procedure there was a code that looked like that:


Select @OldValue = Col1 from MyTable where PK=X
Update MyTable SET Col1 = NewValue where PK=X



I wanted to access the table only once instead of twice.
Adi

--------------------------------------------------------------
To know how to ask questions and increase the chances of getting asnwers:
http://www.sqlservercentral.com/articles/Best+Practices/61537/

For better answers on performance questions, click on the following...
http://www.sqlservercentral.com/articles/SQLServerCentral/66909/
Koen Verbeeck
Koen Verbeeck
SSCoach
SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)SSCoach (16K reputation)

Group: General Forum Members
Points: 16441 Visits: 13202
Adi Cohn-120898 (7/9/2013)
Jeff – Sorry for disappearing, but for some reason I missed your response. What I wanted to do was very simple. I was working on improving performance on a stored procedure. One of the changes that I've made was to make fewer data access statements. In the procedure there was a code that looked like that:


Select @OldValue = Col1 from MyTable where PK=X
Update MyTable SET Col1 = NewValue where PK=X



I wanted to access the table only once instead of twice.
Adi


You are right to make such an improvement. The old code is not efficient.



How to post forum questions.
Need an answer? No, you need a question.
What’s the deal with Excel & SSIS?

Member of LinkedIn. My blog at SQLKover.

MCSA SQL Server 2012 - MCSE Business Intelligence
SwePeso
SwePeso
SSCrazy
SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)SSCrazy (2.5K reputation)

Group: General Forum Members
Points: 2469 Visits: 3431
Why not use the OUTPUT clause?


N 56°04'39.16"
E 12°55'05.25"
Jeff Moden
Jeff Moden
SSC-Forever
SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)SSC-Forever (44K reputation)

Group: General Forum Members
Points: 44994 Visits: 39880
Adi Cohn-120898 (7/9/2013)
Jeff – Sorry for disappearing, but for some reason I missed your response. What I wanted to do was very simple. I was working on improving performance on a stored procedure. One of the changes that I've made was to make fewer data access statements. In the procedure there was a code that looked like that:


Select @OldValue = Col1 from MyTable where PK=X
Update MyTable SET Col1 = NewValue where PK=X



I wanted to access the table only once instead of twice.
Adi


The problem with that is that it will only handle one row at a time. I agree that's the way you designed it with the PK=X but what is the larger picture? Is this something that you need to do with a batch of rows?

--Jeff Moden

RBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
     Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
Although they tell us that they want it real bad, our primary goal is to ensure that we dont actually give it to them that way.
Although change is inevitable, change for the better is not.
Just because you can do something in PowerShell, doesnt mean you should. Wink

Helpful Links:
How to post code problems
How to post performance problems
Forum FAQs
Adi Cohn-120898
Adi Cohn-120898
SSCrazy
SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)SSCrazy (2.2K reputation)

Group: General Forum Members
Points: 2222 Visits: 6076
Jeff Moden (7/20/2013)
Adi Cohn-120898 (7/9/2013)
Jeff – Sorry for disappearing, but for some reason I missed your response. What I wanted to do was very simple. I was working on improving performance on a stored procedure. One of the changes that I've made was to make fewer data access statements. In the procedure there was a code that looked like that:


Select @OldValue = Col1 from MyTable where PK=X
Update MyTable SET Col1 = NewValue where PK=X



I wanted to access the table only once instead of twice.
Adi


The problem with that is that it will only handle one row at a time. I agree that's the way you designed it with the PK=X but what is the larger picture? Is this something that you need to do with a batch of rows?


It will always be for 1 record. If this would have been with more then few records, I would have used output clause with temporary table.

Adi

--------------------------------------------------------------
To know how to ask questions and increase the chances of getting asnwers:
http://www.sqlservercentral.com/articles/Best+Practices/61537/

For better answers on performance questions, click on the following...
http://www.sqlservercentral.com/articles/SQLServerCentral/66909/
Go


Permissions

You can't post new topics.
You can't post topic replies.
You can't post new polls.
You can't post replies to polls.
You can't edit your own topics.
You can't delete your own topics.
You can't edit other topics.
You can't delete other topics.
You can't edit your own posts.
You can't edit other posts.
You can't delete your own posts.
You can't delete other posts.
You can't post events.
You can't edit your own events.
You can't edit other events.
You can't delete your own events.
You can't delete other events.
You can't send private messages.
You can't send emails.
You can read topics.
You can't vote in polls.
You can't upload attachments.
You can download attachments.
You can't post HTML code.
You can't edit HTML code.
You can't post IFCode.
You can't post JavaScript.
You can post emoticons.
You can't post or upload images.

Select a forum

































































































































































SQLServerCentral


Search