Stored procedure question

  • Hello, i have the following code in a stored procedure that is not working:

    SET @sqlStmt1 = 'SELECT Cast(c.COLUMN_NAME As varchar(100)) + '' + '' + '''''',''''''

    FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,

    INFORMATION_SCHEMA.KEY_COLUMN_USAGE c

    WHERE pk.TABLE_NAME =' + '''' + @i_tab_nm + '''' +

    ' AND CONSTRAINT_TYPE = ''PRIMARY KEY''

    AND c.TABLE_NAME = pk.TABLE_NAME

    AND c.CONSTRAINT_NAME = pk.CONSTRAINT_NAME'

    EXECUTE (@sqlStmt1)

    -- Removes the unnecessary characters from the end.

    SET @v_pkStr = SUBSTRING(@v_pkStr, 1, Len(@v_pkStr) - 6)

    SELECT '@v_pkStr: ' + @v_pkStr

    My question is how can I put the results of the EXECUTE into a variable for use later in my SP?

    Best Regards,

    ~David

  • I'm not sure you need the dynamic SQL there since your only variable is after the = sign in the query.

    To answer your question, yes, you could use it later in the query if it ran without error.

    The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge. - Stephen Hawking

  • Hello,

    From what you posted, the dynamic sql is not necessary. If the table name is passed into the stored procedure as a variable (say @table_name varchar(100)), then your query would look something like this:

    Select @Col_Name=c.column_name from INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk, INFORMATION_SCHEMA.KEY_COLUMN_USAGE c

    Where CONSTRAINT_TYPE='Primary Key' and c.TABLE_NAME=pk.TABLE_NAME

    and c.CONSTRAINT_NAME=pk.constraint_name and pk.TABLE_NAME=@table_name

    The result of the query will be held in the variable "@Col_name"

    HTH

    Elliott

  • Also, you should rewrite the query to use an INNER JOIN rather than the older way its using more than one table.

    The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge. - Stephen Hawking

  • Okay, the sp is not working. Here is the entire sp:

    The code in bold is not working. The @v_pkStr variable is always NULL.

    ALTER PROCEDURE [esell].[SP_VERIFY_DFT_COLUMNS]

    @i_tab_nm NVARCHAR(100),

    @i_col_lst NVARCHAR(100),

    @o_rtn_cd INT OUTPUT

    AS

    DECLARE

    @Parameter NVARCHAR(4000),

    @sqlStmt NVARCHAR(4000),

    @sqlStmt1 NVARCHAR(4000),

    @v_pkStr NVARCHAR(4000),

    @cnt INT,

    @tmpMessage NVARCHAR(2000),

    @Counter INT,

    @colNm NVARCHAR(25)

    BEGIN TRY

    --SELECT @i_tab_nm

    --SELECT @i_col_lst

    CREATE TABLE ##Tally

    (N INT,

    CONSTRAINT PK_Tally_N PRIMARY KEY CLUSTERED (N)

    )

    SET @Counter = 1

    WHILE @Counter <= 11000

    BEGIN

    INSERT INTO ##Tally

    (N)

    VALUES (@Counter)

    SET @Counter = @Counter + 1

    END

    SELECT @v_pkStr = @v_pkStr + 'CAST(' + Cast(c.COLUMN_NAME As varchar(100)) + ' AS VARCHAR(100))' + '+' + ''',''' + '+'

    FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,

    INFORMATION_SCHEMA.KEY_COLUMN_USAGE c

    WHERE pk.TABLE_NAME = @i_tab_nm

    AND CONSTRAINT_TYPE = 'PRIMARY KEY'

    AND c.TABLE_NAME = pk.TABLE_NAME

    AND c.CONSTRAINT_NAME = pk.CONSTRAINT_NAME

    -- Removes the unecessary characters from the end.

    SET @v_pkStr = SUBSTRING(@v_pkStr, 1, Len(@v_pkStr) - 5)

    --===== Create a table to store the results in

    DECLARE @Elements TABLE

    (

    Number INT IDENTITY(1,1), --Order it appears in original string

    Value VARCHAR(50)--The string value of the element

    );

    --===== Add start and end commas to the Parameter so we can handle -- single elements

    SET @Parameter = ','+ @i_col_lst +','

    INSERT INTO @Elements

    (Value)

    SELECT SUBSTRING(@Parameter,N+1,CHARINDEX(',',@Parameter,N+1)-N-1)

    FROM ##Tally

    WHERE N < LEN(@Parameter)

    AND SUBSTRING(@Parameter,N,1) = ',' --Notice how we find the comma

    SET @cnt = @@ROWCOUNT

    --select * from @Elements

    WHILE @cnt > 0

    BEGIN

    SELECT @colNm = value FROM @Elements WHERE Number = @cnt

    SELECT @sqlStmt = 'INSERT INTO data_validation_log SELECT ' + '''' + @i_tab_nm + '''' + ', ' + '''' + @colNm + ''''

    + ', ' + @v_pkStr + ' FROM ' + @i_tab_nm + ' WHERE ' + @colNm + ' IS NULL OR ' + @colNm + ' = '''' ' ;

    EXECUTE (@sqlStmt)

    SET @cnt = @cnt -1

    END

    DROP TABLE ##tally

    END TRY

    BEGIN CATCH

    SET @tmpMessage = 'Error ' + CAST(ERROR_NUMBER() AS VARCHAR) + ' error in stored procedure ' +

    ' at line ' + CAST(ERROR_LINE() AS VARCHAR) + ': ' + ERROR_MESSAGE()

    RAISERROR(@tmpMessage, 15, 1);

    -- Return a NON successful code ==> -1

    SELECT @o_rtn_cd = -1

    END CATCH

    Best Regards,

    ~David

  • The problem is right here

    SELECT @v_pkStr = @v_pkStr

    You define the variable but nothing is assigned to it so at this point it's value is NULL. NULL + anything will always be NULL.

    The value should be what you expect it to be if you don't try to append a NULL string.

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  • mtillman-921105 (3/11/2011)


    Also, you should rewrite the query to use an INNER JOIN rather than the older way its using more than one table.

    There's no performance gain in it. The only supposed advantage is that you can more easily tell if you've missed a join... Heh... I'm not buying that one either. 🙂

    --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)
    Intro to Tally Tables and Functions

  • Jeff Moden (3/11/2011)


    mtillman-921105 (3/11/2011)


    Also, you should rewrite the query to use an INNER JOIN rather than the older way its using more than one table.

    There's no performance gain in it. The only supposed advantage is that you can more easily tell if you've missed a join... Heh... I'm not buying that one either. 🙂

    The reason is not performance. The older way of using multiple tables seperated by commas (rather than using JOINs) has been degraded and may not be supported in future versions of SQL. Or, at least that's my understanding. But maybe you know something I don't - has that changed?

    The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge. - Stephen Hawking

  • This is correct and I have modified my code to adhere to the new join syntax. Thank you!

    David

    Best Regards,

    ~David

  • mtillman-921105 (3/14/2011)


    Jeff Moden (3/11/2011)


    mtillman-921105 (3/11/2011)


    Also, you should rewrite the query to use an INNER JOIN rather than the older way its using more than one table.

    There's no performance gain in it. The only supposed advantage is that you can more easily tell if you've missed a join... Heh... I'm not buying that one either. 🙂

    The reason is not performance. The older way of using multiple tables seperated by commas (rather than using JOINs) has been degraded and may not be supported in future versions of SQL. Or, at least that's my understanding. But maybe you know something I don't - has that changed?

    Understood. It'll be interesting to see if they actually do that, though, because not supporting it would make the construction of correlated subqueries and Cross Apply's a whole lot different.

    --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)
    Intro to Tally Tables and Functions

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