Idempotent SQL change script

Today I had a small chat with one of our developers, about adding a column to a table "the right way". I told him, that depending on how they needed to deploy it, it might be beneficial to make it idempotent.

Heres's an example of that script:

USE [M42Demo]; IF COL_LENGTH('dbo.QA', 'minnyecol') IS NULL BEGIN ALTER TABLE [dbo].[QA] ADD minnyecol VARCHAR(2000) NULL; PRINT 'Added column ''minnyecol'' to [dbo].[QA]'; END ELSE PRINT 'Column ''minnyecol'' already exists in [dbo].[QA]';