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vtable

karthik M

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June 25, 2008 at 2:48 am

#71618

All,
I have faced a different problem recently.
When i executed a procedure from back end, it works fine.
But when i executed the same procedure from UI, it is not giving the proper result.
I also identified the problem.
The problem is
i have one condition in my procedure. The procedure will get value from the front end.
If ( @MID = Null and @sp-2 = Null and @ACls = Null and @sid = Null and @SDetId = Null)
which I changed to this
If ( @MID is Null and @sp-2 is Null and @ACls is Null and @sid is Null and @SDetId is Null)
then it works fine from UI.
I remember one rule about NULL. Two nulls are not equal.
I also have studied an article here about Difference between =NULL and IS NULL. In that article he mentioed about vtable ( to store table variables). As i want to know more about it,I have searched on websites, but i can't get any clear information.
It would be appreciated if anyone give more information on that.
karthik

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PrabodhM Ten Centuries Points: 1304 More actions · Answer 1

PrabodhM

Ten Centuries

Points: 1304

June 25, 2008 at 5:27 am

#833819

See usage of SET ANSI_NULLS ON|OFF

Jeff Moden SSC Guru Points: 1003857 More actions · Answer 2

Change the default setting will likely open a huge can of worms for you... lot's of other folks code depends on NULLs not being equal to anything and changing that setting will break ALL of that code.

So far as "vtables" go, are you talking about "Table Variables"?

--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.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

Jeff Moden SSC Guru Points: 1003857 More actions · Answer 3

Sorry... you are talking about "Table Variables"... best to look up about those in Books Online and take a look at the following article...

http://support.microsoft.com/default.aspx?scid=kb;en-us;305977&Product=sql2k

--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.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

karthik M One Orange Chip Points: 29139 More actions · Answer 4

Thanks Jeff and prabodh.

So far as "vtables" go, are you talking about "Table Variables"?

No.

I understood the difference between =NULL,ISNULL and SET ANSIL NULL ON/OFF after reading the below article.

http://www.sqlservercentral.com/articles/Basic+Querying/understandingthedifferencebetweenisnull/871/

In this article, he has used vtable, just i wanted to know more about that.

karthik

Jeff Moden SSC Guru Points: 1003857 More actions · Answer 5

Ah... got ya...

Nope... I don't know, at the machine language level, what the memory address of vtable in SQL Server is.

--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.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)