jwcolby
jwcolby at colbyconsulting.com
Thu Jan 19 09:07:48 CST 2012
I have built several SQL Server databases which are used by Access, and have just recently discovered that I really need a timestamp in every table. So I have been laboriously adding a timestamp field table by table. As everyone knows, TSQL is not my strength, but I went out looking for solutions to doing this programmatically using TSQL. So the challenge is to get every user table in a database, and then execute an alter table statement: alter table EachTableName add timestamp I managed to do it but boy is it *not* elegant! I found the following (by our own Arthur Fuller) which creates a udf to return a table with the names of all the users tables. My first iteration actually created this udf and then called it. http://www.techrepublic.com/article/alter-every-table-in-a-sql-database/5796376 The following discusses iterating through a table. The author was executing a stored procedure for each line of the table, which is close to what I am trying to do. Yes, I know RBAR and all that but after all this is just a minimal number of operations done once per database. http://weblogs.asp.net/jgalloway/archive/2006/04/12/442618.aspx That said, I would like to know if there is an elegant (set based) way to execute a line of code like I am doing for each record in the table. If you promise not to laugh I will show you my cobbled together solution. I built a User Stored Procedure so that I can just copy it over to my server at the client. The stored procedure creates the udf every time it runs, this in case this is the first time I am running the USP. I then declare a table to store the table returned by the UDF, and fill the table. After that I iterate the table RBAR, pulling the assembled SQL statement out into a varchar, and then exec() the SQL Statement. -- ============================================= -- Author: <jwc> -- Create date: <1/19/2012> -- Description: <Add a timestamp field to every user table> -- ============================================= ALTER PROCEDURE [dbo].[usb_AddFldTake2] @DBName as varchar(250) AS BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON; DECLARE @SQL varchar(4000) DECLARE @tblUsrTableNames table (rownum int IDENTITY (1, 1), TblName varchar(250)) --Get all of the table names into a table variable select @SQL = 'SELECT TOP 100 PERCENT name FROM ' + @DBName + '.dbo.sysobjects WHERE type = ''U'' ORDER BY name' print @SQL insert into @tblUsrTableNames (TblName) exec (@SQL) --Set up RBAR table iteration declare @RowCnt int declare @MaxRows int select @RowCnt = 1 select @MaxRows=count(*) from @tblUsrTableNames Declare @TblName varchar(250) while @RowCnt <= @MaxRows begin --Get the name of the table from each row select @TblName = (SELECT TblName from @tblUsrTableNames where rownum = @RowCnt ) --build a sql statement to perform the alter table and add the timestamp select @SQL = 'ALTER TABLE PrisonMinistries.dbo.[' + @TblName + '] ADD timestamp' print @SQL --Execute the sql execute (@SQL) --move to the next row Select @RowCnt = @RowCnt + 1 end -- Insert statements for procedure here END As I mentioned I would like to know if there is an elegant (set based) way to execute a line of code like I am doing for each record in the table. -- John W. Colby Colby Consulting Reality is what refuses to go away when you do not believe in it