Is it advisable to use a temp table when the stored procedure could be run simultaneously by different users?

I am working on a stored procedure that retrieves the objectGUID from active directory. I am storing the result in a temp table and then returning the value in an output parameter for use with other processes. The SP will be called from different stored procedures as well as web applications PHP, ASP Classic and ASP.Net.

I read HERE that (regarding temp tables):


If created inside a stored procedure they are destroyed upon completion of the stored procedure. Furthermore, the scope of any particular temporary table is the session in which it is created; meaning it is only visible to the current user. Multiple users could create a temp table named #TableX and any queries run simultaneously would not affect one another - they would remain autonomous transactions and the tables would remain autonomous objects. You may notice that my sample temporary table name started with a "#" sign.

Sounds like I am good to go but I wanted to get some advice to make sure there aren't any gotchas I am unaware of. Here is the SP.

Thanks in advance.

CREATE PROCEDURE stp_adlookup
@user varchar(100),
@objectGUID varbinary(256) OUTPUT
AS
SET NOCOUNT ON;
DECLARE @qry char(1000)
CREATE TABLE #tmp(
objectGUID nvarchar(256)
)

SET @qry = 'SELECT *
FROM openquery(ADSI, ''
SELECT  objectGUID              
FROM    ''''LDAP://mydomaincontroller.com''''
WHERE sAMAccountName = ''''' + @user + '''''
'')'
INSERT INTO #tmp
EXEC(@qry)
SELECT @objectGUID=CAST(objectGUID as varbinary(256))  FROM #tmp;
DROP TABLE #tmp
SET NOCOUNT OFF;
GO

Yes, each user will get their own copy of the #temp table, even if they run at the exact same time.

(However, don't use global ##temp tables, signified with two leading pound/hash signs.)

But why do you need a #temp table here at all? Something like this should work (untested, as I don't have LDAP anywhere near me):

CREATE PROCEDURE dbo.stp_adlookup -- ALWAYS use schema prefix
  @user varchar(100),
  @objectGUID varbinary(256) OUTPUT
AS
BEGIN -- use body wrappers
  SET NOCOUNT ON;

  DECLARE @qry nvarchar(max); -- don't use CHAR for dynamic SQL

  SET @qry = N'SELECT @o = objectGUID
    FROM openquery(ADSI, ''SELECT  objectGUID              
      FROM    ''''LDAP://mydomaincontroller.com''''
      WHERE sAMAccountName = ''''' + @user + ''''''')';

  -- can probably parameterize the above, but those single
  -- quotes are a nightmare. Not sure if they're necessary
  -- but I do not feel like trying to untangle them.

  EXEC sys.sp_executesql @qry, N'@o UNIQUEIDENTIFIER', @o = @objectGUID OUTPUT;

  -- SET NOCOUNT OFF; -- don't do this.
END
GO

StackExchange Database Administrators Q#86526, answer score: 15