Solved

T-SQL: Stored Procedure - variable assignment

Posted on 2010-11-24
3
446 Views
Last Modified: 2012-05-10
Techies--
Why does @TestCaseStatement in the code snippet fail to set to any value when variables are empty? I am trying to output to a table the values of variables whether they contain strings, integers or are just unset.

Also,  when I get this to work, I want to import this logic into a program that has multiple transactions -- how do I manage
the GOTO routine so as to avoid the write to the error/debug log under ProcessDEBUG: from being treated as part of an existing transaction? Finally, what happens on a return in a GOTO when called while processing a transaction?




DECLARE @dbgFlag bit

DECLARE @TestCaseStatement nvarchar(max)



SET @dbgFlag = 'True'



IF(@valTest = 'GO')

 BEGIN



-- ##DEBUG

   IF (@dbgFlg = 'True')

    BEGIN

     -- // this works because @StrikeTypeName is set to a value like 'Field'

     -- SET @TestCaseStatement = 'UPDATE s1: StrikeTypeName incoming: ' + 

     --   @StrikeTypeName + ' conditioned      lowercase: ' + @StrikeTypeName + 

     -- ' PatClassTypeID: ' + convert(varchar(10),@PatClassTypeID) 

     -- // This did NOT work, because the incoming values are not set to anything.

     -- SET @TestCaseStatement = 'UPDATE s2: ret_myDesignID incoming: ' + 

     -- convert(varchar(10),@ret_myDesignID) + ' BOPatternNum incoming: ' + 

     -- @BOPatternNum + ' BOPatternID: ' + convert(varchar(10),@BOPatternID)

     

     -- // This worked because I forced a value of '103'.

     SET @TestCaseStatement = 'UPDATE s2: ret_myDesignID incoming: ' + convert(varchar(10),103)



     PRINT @TestCaseStatement

     GOTO ProcessDEBUG



    END



 END



ProcessDEBUG:



INSERT INTo SHG_ErrorLog 

 (EntryDate,

  AppName,

  ErrorMsg

 )

VALUES

 (getdate(),

  'DASH',

  @TestCaseStatement

 )



return

Open in new window

0
Comment
Question by:ditallop
  • 2
3 Comments
 
LVL 142

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 500 total points
ID: 34206302
that is because 'string' + NULL returns NULL ...

so, you need to handle NULL value in your case of building the SQL.

     SET @TestCaseStatement = 'UPDATE s2  SET ret_myDesignID = ' + CASE WHEN @ret_myDesignID IS NULL THEN 'NULL' ELSE CAST(@ret_myDesignID as varchar(10)) END + ' ' 

Open in new window

and in case the field is varchar:
     SET @TestCaseStatement = 'UPDATE s2  SET ret_myDesignID = ' + CASE WHEN @ret_myDesignID IS NULL THEN 'NULL' ELSE '''' + CAST(@ret_myDesignID as varchar(10)) + '''' END + ' ' 

Open in new window

0
 

Author Comment

by:ditallop
ID: 34206454
Thanks! BTW, on the second half of the question -- what happens under a goto with a return when processing a transaction--and is it possible to isolate the insert to the debug log outside of the transaction assumption that the insert to the debug logger is part of a specific transaction?  what i want to do is be able to use this goto from whatever transaction i happen to be on --
0
 
LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 34206503
you have to ensure that your procedure does COMMIT/ROLLBACK need to be balanced.
so, if you have a BEGIN TRANSACTION, and RETURN without a COMMIT/ROLLBACK, you will have the result that if the calling code does not commit on it's turn, the transaction is rolled back.

so, for the debug, you can rollback explicitly (if a transaction has been started, check @@trancount value), and begin + commit a transaction for the debug stuff apart.
0

Featured Post

Zoho SalesIQ

Hassle-free live chat software re-imagined for business growth. 2 users, always free.

Join & Write a Comment

If you having speed problem in loading SQL Server Management Studio, try to uncheck these options in your internet browser (IE -> Internet Options / Advanced / Security):    . Check for publisher's certificate revocation    . Check for server ce…
So every once in a while at work I am asked to export data from one table and insert it into another on a different server.  I hate doing this.  There's so many different tables and data types.  Some column data needs quoted and some doesn't.  What …
Excel styles will make formatting consistent and let you apply and change formatting faster. In this tutorial, you'll learn how to use Excel's built-in styles, how to modify styles, and how to create your own. You'll also learn how to use your custo…
When you create an app prototype with Adobe XD, you can insert system screens -- sharing or Control Center, for example -- with just a few clicks. This video shows you how. You can take the full course on Experts Exchange at http://bit.ly/XDcourse.

758 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now