ActiveRecord: Never forget there's a database

Some lessons learned while using ActiveRecord.

I really like ActiveRecord and I would recommend using it on .NET projects when there is the need an OR Mapping tool.  The fault lay was us, the developers.  We didn't pay enough attention to the fact that there was a database at the end of the calls that the repository was making.  We didn't spot that some of the calls which our test code was making were potentially very expensive in real usage scenarios.  And so we got bitten by the law of leaky abstractions, which manifest itself through a number of bad usage patterns which caused immediate performance problems.

Read the full post for other lessons.