JDBC stands for database connectivity. JDBC is a sql level API that allows to execute SQL statement and retrieve results if any.

Two & Three Tier Databse Access Models :

The JDBC provides support for both two and three tier database access models.

Two Tier Model :

The java application lacks direct communication to the database. Hence it communicates directly to database and the results of these are then sent from database back to application.

Three Tier Model :

In Three tier model, the JDBC driver send commands to middle tier, which is then send commands to the database. The results are sent back to the middle tier which communicates them back to the application.

Advantage :

They have direct interface with database .

Disadvantage:

A defect in a driver’s native code section can crash the entire server.