"Comdb2 is a relational database built in-house at Bloomberg L.P. over the last 14 years or so. It started with a modest goal of replacing an older home-grown system to allow databases to stay in sync easier. SQL was added early in its development, and it quickly started replacing other relational databases in addition to its original goal. Comdb2 today holds a good chunk of Bloomberg's data, and is continually developed by a dedicated team."