Preserve SQL Indexes While Altering Column Datatype

Question

I have a smalldatetime column that I need to alter to be a datetime column. This is something that will be part of an install process, so it cannot be a manual procedure. Un

Answer 1

EDIT: It depends on the original and changed datatype. If you try to alter a column from varchar to nvarchar, it will fail. Whereas, if you alter column from varchar(16) to varchar(32), it will succeed.

--Disable Index
ALTER INDEX MyIndex ON MyTable DISABLE
GO

-- Change column datatype

--Enable Index
ALTER INDEX MyIndex ON MyTable REBUILD
GO

If you change the type of a column, then all indexes that use that column will have to be rebuilt.

But unless you have huge volumes of data (or run 24/7), rebuilding indexes is no big deal. Just schedule a maintenance window.