Add column to table and then update it inside transaction

Handling Transactions with Style

Dealing with ALTER TABLE and UPDATE in a transaction requires a bit of finesse. Here's how to make your SQL code as sleek as a new sports car:

Batch Commands Separation & Exception Handling

Combine the agility of a ninja with the precision of a surgeon:

• Separate your commands: Keep ALTER TABLE and UPDATE commands in different batches to prevent GO from going crazy.

• Handle exceptions: Put those exceptions in a try-catch block to ensure no surprises. After all, unexpected SQL errors are scarier than horror movie jump-scares!

XACT_ABORT: The Hero in Shining Armor

If your SQL code was a superhero movie, SET XACT_ABORT ON would definitely be wearing the cape:

SET XACT_ABORT ON; -- Now serving: Consistent transactions!
BEGIN TRANSACTION;
-- Your very important operations!
COMMIT TRANSACTION;
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• What's so cool about it?: It's like an automatic insurance for your transaction which rolls back any action at the first sign of trouble. This maintains the integrity of your operation, so you can rest easy knowing your data stays consistent, no matter what.

Checking for Column Existence

Why add a column that already exists? That's as pointless as a screen door on a submarine!

IF NOT EXISTS(SELECT * FROM sys.columns 
               WHERE Name = N'NewColumn' AND Object_ID = Object_ID(N'YourTable'))
BEGIN
    -- Your column addition logic: making SQL magic!
END
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• Keep it Dynamic: Use sp_executesql and keep the entire operation within a transaction, enacting the law of atomicity.

Dealing with GUIDs

Ah, the GUIDs - handle with care if you want to avoid a crowded party of duplicate identifiers.

• Avoid Generic Defaults: Giving all rows the same GUID is like calling everyone at a party "Bob". Quite confusing, right?

• The Trick: Initialize each row with a unique value using NEWID() or NEWSEQUENTIALID(), when setting the column default value.

Practical Strategies

Crossing the bridge from theory to practical use should be as smooth as driving a luxury sedan on an open highway.

Managing Errors

• Try-Catch Blocks: Prevent SQL spill-overs with the TRY...CATCH mechanism.
• Checking Transaction State: XACT_STATE() is your secret agent determining if your transaction's health bar is full enough after an attack.

Preserving the Schema

• Default Values: Consideration about default values equals sparing future headaches. Especially with uniqueidentifier columns, you might want to drop the default constraint post-updating.
• Choose your DataType: When in doubt, NVARCHAR(256) it!

Using Tools & References

• Red Gate SQL Compare: Like having a walking, talking SQL guru by your side.
• SQL Server Forums & Official Documentation: When you are lost, let thousands of SQL enthusiasts guide you back!