Relational database management systems, or RDBMS, have for decades been at the core of large-scale, mission-critical software systems. At first, although there was consensus on the concepts of relational data, individual vendors defined their own APIs to support client software. The Structured Query Language, or SQL, was an early point of commonality, but even this was not well standardized at first. Much greater variation was found in the means of connecting to a database, authentication, and other peripheral actions.

Despite increasing standardization, there is still the threat of "vendor lock-in" in the modern RDB marketplace. JDBC, then, provides two things. The more basic of these is a simple Java API for building SQL queries, inserts, updates, and deletions. The more important, though, is a driver-based architecture by which this API is portable over any relational data source - so long as a JDBC driver can be bought or built.

JDBC allows a Java component to translate application data from its relational form into Java objects and primitive values - application code can handle the data from there however it wishes.