A euphemism for douche bag, perfect for the work setting. The origin of this meaning most certainly came from a computer science setting, where the term "database" is thrown around so much it was eventually used as a derogatory term.
Boss: "So, what do you think of our new general manager?"
Me: "That guy's a real database."
Boss: "Yes, I suppose he does store a lot of information. (chuckles)"