F IGURE 7.3
The Type 1 JDBC-ODBC Bridge.
Type 3: JDBC-Net, Pure Java Driver
The JDBC-Net drivers are a three-tier solution. This type of driver translates JDBC calls into a
database-independent network protocol that is sent to a middleware server. This server then
translates this DBMS-independent protocol into a DBMS-specific protocol, which is sent to a
particular database. The results are routed back through the middleware server and sent back to
the client. This type of solution makes it possible to implement a pure Java client. It also
makes it possible to swap databases without affecting the client. This is by far the most flexible
JDBC solution. Figure 7.5 shows this three-tier solution.