Programatically find and apply schema differences on SQL Server

Question

I have a product that I'm currently authoring that relies on SQL server for the backend. One issue I'm trying to resolve is to improve the 'upgrade' story. So v1 will have a particular schema and v2 may include some enhancements to this schema (new tables and new columns).

I'm aware of the SDKs from RedGate and ApexSQL - but would like to avoid.

I've had a read through the SMO docs, but I'm new to it and struggling to see if this can be applied in this situtaiton. Ideally, I'd like this to make this programatic (SMO or other) - the base cases seems straight forward enough, but I really don't want to re-invent the wheel if I can help it. Does anyone have any experience of similar requirements or ideas about how I could approach?

Answer 1

Maybe not exactly what your're looking for (since it's not SMO) but having a look at Entity Framework Code First Migrations might help you:

http://msdn.microsoft.com/en-us/data/jj591621

Changes in the model-classes can be versioned and can either be applied directly to a database or, if you do not have direct access to your database, you can generate SQL-Code for your new version and hand it to your database-administrator.

Answer 2

You don't say what version of SQL Server you're using but in (I think) 2005 and beyond, there is the concept of database triggers. These work like their table level cousins but can be used to track any kind of DDL change that happens on the database. We didn't use it to actually generate DDL - more to track when the format of a table changed. Although what you're after should be possible I'd have thought.

Triggers are one of those things that divide developers. Some people think they're the best thing since sliced bread whilst others hate them with a passion. Perhaps because when data changes, these are the last thing you think of.

Answer 3

I us Database Projects in Visual Studio to mange versioning of schemas. Once you create a baseline in a Database Project, you can make your changes in the project and then use the Schema Compare to create SQL scripts to apply the changes in different environments.

I would recommend doing only additive changes, but it will generate change scripts for destructive changes. If you do not have your environments synced up, I strongly recommend generating a new script for each environment.

This blog post goes over how to create one in Visual Studio 2012: http://candordeveloper.com/2013/01/08/creating-a-sql-server-database-project-in-visual-studio-2012/

Red Gate has a schema compare product too, but I have not really used it.