Create column and insert into it within the same transaction?

Question

Is it possible to create a column and insert values to it during the same transaction? This is part of an upgrade script. I found the following method online, but it does not work; I get an error: Invalid column name 'IndexNumber'.. I'm assuming this is because the transaction hasn't created the column yet so there is nothing to insert to.

The relevant parts of my script:

Print 'Beginning Upgrade'
Begin Transaction
    -- --------------------------------------------------------------------
    USE [MyDatabase];

    /* Widgets now can be ordered and the order can be modified */
    ALTER TABLE [dbo].[Widgets] ADD [IndexNumber] [int] NULL;

    DECLARE @ind INT 
    SET @ind = 0 
    UPDATE [dbo].[Widgets]
    SET @ind = [IndexNumber] = @ind + 1;

    ALTER TABLE [dbo].[Widgets] ALTER COLUMN [IndexNumber] [int] NOT NULL;
    -- --------------------------------------------------------------------
Commit tran
Print 'Upgrade completed'

The reason why [IndexNumber] is not an identity column is that it must be editable.

Answer 1

Another alternative, if you don't want to split the code into separate batches, is to use EXEC to create a nested scope/batch:

Print 'Beginning Upgrade'
Begin Transaction
    -- --------------------------------------------------------------------
    USE [MyDatabase];

    /* Widgets now can be ordered and the order can be modified */
    ALTER TABLE [dbo].[Widgets] ADD [IndexNumber] [int] NULL;

    EXEC('DECLARE @ind INT 
    SET @ind = 0 
    UPDATE [dbo].[Widgets]
    SET @ind = [IndexNumber] = @ind + 1;');

    ALTER TABLE [dbo].[Widgets] ALTER COLUMN [IndexNumber] [int] NOT NULL;
    -- --------------------------------------------------------------------
Commit tran
Print 'Upgrade completed'

The reason why the original code doesn't work because it tries to compile the entire batch before running it - the compilation fails and so it never even starts the transaction, let along alters the table.

Answer 2

You cannot add a new column and use it within the same batch. You need to insert GO between adding a column and using it.

Transaction is still ok (you can test that by changing Commit tran to rollback tran to see no changes were committed).

Print 'Beginning Upgrade'
Begin Transaction
    -- --------------------------------------------------------------------
    USE [MyDatabase];

    /* Widgets now can be ordered and the order can be modified */
    ALTER TABLE [dbo].[Widgets] ADD [IndexNumber] [int] NULL;

    GO

    DECLARE @ind INT 
    SET @ind = 0 
    UPDATE [dbo].[Widgets]
    SET @ind = [IndexNumber] = @ind + 1;

    ALTER TABLE [dbo].[Widgets] ALTER COLUMN [IndexNumber] [int] NOT NULL;
    -- --------------------------------------------------------------------
Commit tran
Print 'Upgrade completed'