JDBC provides a standard library for accessing relational data, allowing users to develop SQL calls using the Java Application Programming Interface (API). The JDBC driver is responsible for the data access communication interface with the database management system (DBMS).
Selecting the appropriate driver is fundamental to improving performance. According to Sun Microsystems, there are four categories of JDBC drivers (Types 1–4), and more than 177 models.
Type 1 – JDBC–Open Database Connectivity (ODBC) bridge:
Type 1 driver provides JDBC access to one or more ODBC drivers. Type 1 drivers assist companies that already possess a large ODBC population with the JDBC educational process. Type 1 drivers are slow, however, because they require JDBC-ODBC translation. As such, they are not well suited for large enterprises.
Type 2 – Partial Java driver:
A Type 2 driver converts the calls made from the JDBC API to the receiving machine’s API for a specific database (DB2, Oracle, Sybase, SQL Server, etc.). A Type 2 driver contains compiled code for the backend system. Type 2 drivers process more quickly than Type 1 drivers. The code must be compiled, however, for every operating system on which the application runs. In Windows NT and z/OS development, organizations may wish to develop with a Type 4 driver and then transition to a Type 2 driver for production.
A Type 2 driver converts the calls made from the JDBC API to the receiving machine’s API for a specific database (DB2, Oracle, Sybase, SQL Server, etc.). A Type 2 driver contains compiled code for the backend system. Type 2 drivers process more quickly than Type 1 drivers. The code must be compiled, however, for every operating system on which the application runs. In Windows NT and z/OS development, organizations may wish to develop with a Type 4 driver and then transition to a Type 2 driver for production.
Type 3 – Pure Java driver for database middleware:
A Type 3 driver provides connectivity to many different databases, translating JDBC calls into the middleware vendor’s protocol and then into the database-specific protocol via the middleware server. A Type 3 driver is often faster than Type 1 and 2 drivers, and is useful if an organization wishes to connect to multiple database types. Database-specific code, however, must reside on the middle tier. If the application is going to run on different operating systems, a Type 4 driver may be more appropriate.
A Type 3 driver provides connectivity to many different databases, translating JDBC calls into the middleware vendor’s protocol and then into the database-specific protocol via the middleware server. A Type 3 driver is often faster than Type 1 and 2 drivers, and is useful if an organization wishes to connect to multiple database types. Database-specific code, however, must reside on the middle tier. If the application is going to run on different operating systems, a Type 4 driver may be more appropriate.
Type 4 – Direct-to-database Java driver:
A Type 4 driver converts JDBC calls into packets that are transferred over the network in the database’s proprietary format, allowing a direct call from the client to the database without a middle tier. Type 4 drivers often offer better performance than Type 1 or 2 drivers; do not require additional code on client or server machines; and can be downloaded dynamically. Type 4 drivers, however, are not optimized for the operating system and are unable to take advantage of operating system features. Users also need a different driver for each different database.
A Type 4 driver converts JDBC calls into packets that are transferred over the network in the database’s proprietary format, allowing a direct call from the client to the database without a middle tier. Type 4 drivers often offer better performance than Type 1 or 2 drivers; do not require additional code on client or server machines; and can be downloaded dynamically. Type 4 drivers, however, are not optimized for the operating system and are unable to take advantage of operating system features. Users also need a different driver for each different database.
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