Walking into a new shop every couple of weeks has its challenges. What sort of problems are they going to throw at me. Recently I had the perfect example of learning more about the data before you start planning out your attack.
In this case the problem was that due to some business rules changes they needed to remove some transactions from their historical data for the last couple of years. I was given a quick summary of the data and let loose on the project. After looking at the sample data which was provided I came up with a plan to resummarize all the data in the fact table for the last couple of years into new tables, then on the night of the release we’d just change the object names and all would be well with the world.
After a few hours of banging my head on the data and not getting the new summary values to match the old data, I started looking at the transactions which needed to be removed. Turns out they were all $0 transactions, so all that needed to happen was that the transaction counts needed to be reduced and the dollar figures weren’t going to be changing at all. Suddenly my job got much easier. Instead of having to do all sorts of math, and figuring out what goes where all I needed to do was a little bit of subtraction. 3 days of work had just been reduced to a few hours.
It just goes to show, that slowing down, taking a little time to learn more about the data that you’ll be working with can go a long way to making your life much easier.