Sun Microsystems JDBC/ODBC Adapter Pure Java driver for database middleware, Type Three Driver

Chapter 1	Section 1.1
Introducing the JDBC/ODBC eWay	About Java Database Connectivity (JDBC)

Figure 2 Typical Type 2 Driver Configuration

The pros and cons for using this type of driver are as follows:

Pros

ƒAllows access to almost any database since the databases ODBC drivers are readily available

ƒOffers significantly better performance than the JDBC/ODBC Bridge

ƒLimited Java feature set

Cons

ƒApplicable Client library must be installed

ƒType 2 driver shows lower performance than type 3 or 4

Pure Java driver for database middleware

This style of driver translates JDBC calls into the middleware vendor's protocol, which is then translated to a DBMS protocol by a middleware server. The middleware provides connectivity to many different databases.

This driver translates JDBC calls into the middleware vendor's protocol, which is then converted to a database-specific protocol by the middleware server software.

Pros: Better performance than Types 1 and 2. Can be used when a company has multiple databases and wants to use a single JDBC driver to connect to all of them. Server-based, so no need for JDBC driver code on client machine. For performance reasons, the back-end server component is optimized for the operating system on which the database is running.

Cons: Needs some database-specific code on the middleware server. If the middleware must run on different platforms, a Type 4 driver might be more effective.

Type Three Driver

A net-protocol fully Java-enabled driver translates JDBC API calls into a DBMS- independent net protocol which is then translated to a DBMS protocol by a server. This net server middleware is able to connect all of its Java technology-based clients to many

JDBC/ODBC eWay Adapter User’s Guide 10 Sun Microsystems, Inc.