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 constitute 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 (as opposed to by a single vendor)
• Nonrelational—vendors that supply prerelational ...