There are many DBMS vendors from which to choose. However, there are definite tiers in terms of popularity, support, and leadership in the DBMS market. In general, the marketplace can be broken down into the following groups:
The Big Three—. the three market leaders that comprise the greater part of the DBMS installed base as well as the bulk of any new sales
The second tier—. large DBMS vendors with stable products, but lagging behind the Big Three in terms of functionality and number of users
Other significant players—. other DBMS vendors with viable, enterprise-capable products
Open-source—. DBMS products supported as open-source software
Nonrelational—. vendors who supply prerelational DBMS products to support legacy ...