JDBC Driver

Type I Drivers
Translates JDBC API calls into Microsoft Open Database Connectivity (ODBC) calls that are then passed to the ODBC driver. The ODBC binary code must be loaded on every client computer that uses this type of driver.Bridge solutions generally require software to be installed on client systems, meaning that they are not good solutions for applications that do not allow you to install software on the client.

Type II Drivers
The type 2 drivers are native API drivers. This means that the driver contains Java code that calls native C or C++ methods provided by the individual database vendors that perform the database access. Again, this solution requires software on the client system.

Type III Drivers
JDBC driver on the client uses sockets to call a middleware application on the server that translates the client requests into an API specific to the desired driver. As it turns out, this kind of driver is extremely flexible since it requires no code installed on the client and a single driver can actually provide access to multiple databases.

Type IV Drivers

Using network protocols built into the database engine, type 4 drivers talk directly to the database using Java sockets. This is the most direct pure Java solution. In nearly every case, this type of driver will come only from the database vendor.
The Red Brick JDBC Driver is a pure Java Type-4 driver based on Version 2.0 of the JDBC API.

Related Technologies
ODBC
Requires configuration (odbc.ini)
RDO, ADO
Requires Win32
OODB
e.g. ObjectStore from ODI
JavaBlend
maps objects to tables transparently (more or less)