Ooh I learned this the hard way even though I'm sure it's well documented.

I have a new problem I have to pay close attention to because of the fact that I share code samples. Because most of my samples are related to data, I frequently share custom sample databases.

As I have written about recently, I have a new computer and decided to install only the latest and greatest. This means I finally moved to SQL Server 2008.

Lack of backwards compatibility is not new for SQL Server and shouldn't come as a big surprise, but I just had not even thought about it.

I have a number of custom databases that I use for my book as well as some demos in my conference presentations. I sent one of those databases to someone who is "quality assurance" testing the walkthroughs and code samples in my book and got an email back from her saying that she couldn't open the file and sent me the error message. The db was incompatible with her version of SQL Server - SQL Server 2005 Express. I thought the issue had to do with a missing log file and spent a little bit of time verifying that this should be okay. Then I focused on the messages complaint that the file version was 655 and only 612 or lower was supported.

This was the clue that the SQL Server 2008 db wouldn't open up in SQL Server 2005.

I thought maybe by changing the compatibility level of the database this would fix the problem, but it doesn't. This blog post by SQL Skills guru, Paul Randal, explains the difference between compatibility level and versions.

So it is a good thing I have backups. But now I need to be very careful about versions when I prepare demos (my presentation laptop is still SQL Server 2005) and share files.