Business Data? Like data that customers pay for us to maintain, internal data like asset tracking (of one sort or another), internal data like project documents, internal data like software written by devs?
Too many options, or just one too broad an option.
Sure, we have an asset (hardware) tracking database but it pretty much blows so I have a database I wrote that provides system tracking with automatic updates of system information. It was a spreadsheet when I got here but I pretty much don't like using spreadsheets as a database so converted it to mysql.
So "in-house; with software I wrote" is a good option too, for a small piece of the business.
[John]