2009

SQL Stored Procedures, UPDATE Template script

Posted By : Shaun McCran
Related Categories: Software Architecture, Best practices, SQL

This article deals with creating a SQL stored procedure for Updating a record.

In each of these stored procedure templates I am declaring a variety of documentation parameters in the header.

I've found these handy in the past when you are working in a team environment, or when you go back to a procedure at a later date. Its much easier to read a simple description in the header, than trawl through the SQL code looking for what it is doing.

So, this declares the procedure name, any parameters and return codes, and also details what it does, and who made it.

In a modified version of this I also hold the SVN revision number here.

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1/********************************************************************************/
2/* Company Name */
3/********************************************************************************/
4/* Procedure Name : dbo.ssp_stored_procname */
5/* Parameters : */
6/* Return Codes : */
7/* */
8/* Description : Description of what it does, params etc */
9/* */
10/* */
11/* */
12/* */
13/* */
14/* Author : Authorname */
15/* Date written : Date */
16/* History : version number */
17/* */
18/********************************************************************************/

The next block of code performs a select on the sysObjects table (part of the Master database). It is checking for the existence of itself. If it finds itself, it will drop the procedure. Note that throughout all of these scripts we are telling the user at each stage what is going on, by printing useful english output back to the screen.

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1IF EXISTS (SELECT 1 FROM sysobjects where id = object_id('dbo.ssp_stored_procname') and sysstat & 0xf = 4)
2BEGIN
3 PRINT 'Dropping old version of dbo.ssp_stored_procname'
4 DROP PROCEDURE dbo.ssp_stored_procname
5END
6GO

By now we have identified whether or not the procedure previously existed, and if it did, we have dropped it, so we know that we are all good to go. So to create our Update procedure, we print out a message to the user, then using the "CREATE PROCEDURE" command we create our procedure.

At this point you substitute the "@field" value with your field name, and the [datatype] and (datasize) with the correct values. Just list your fields one after another, seperating with a comma. As this is creating an Update stored procedure I will list any of the values to update in the query here.

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1PRINT 'Creating procedure dbo.ssp_stored_procname - START'
2GO
3
4CREATE PROCEDURE dbo.ssp_stored_procname
5    (@field         [datatype](datasize),
6     @field         [datatype],
7     @field        [datatype](datasize),
8     @field        [datatype](datasize),
9     @field        [datatype],
10     @field        [datatype])

After that we create the SQL code, as per usual. We have an Update statement, using the variables declared above in the SQL variable declaration (@var). Just write out your update like you normally would here. Then we check for any errors, and return a success message if it all worked ok!

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1AS UPDATE tablename
2SET [field]     = @field,
3 [field]     = @field,
4 [field]     = @field,
5 [field]     = @field,
6 [field]     = @field
7WHERE
8    ( [field] = @conditions)
9RETURN @@ERROR
10GO
11PRINT 'Creating procedure dbo.ssp_stored_procname - END'
12GO

By using a script like this I've found that its really simple to have a repeatable standard process that is easy to implement across a team of developers, ensuring you get the same results, no matter who writes the query. It is also very useful if you have a seperate implementation team, as these scripts are re-runnable, they clear up after themselves.

Download the full template here.