Friday, February 17, 2012

JDBC Driver and Its Types

The JDBC DriverManager class defines objects which can connect Java applications to a JDBC driver. DriverManager has traditionally been the backbone of the JDBC architecture. It is quite small and simple.

Types of JDBC drivers

This topic defines the Java(TM) Database Connectivity (JDBC) driver types. Driver types are used to categorize the technology used to connect to the database. A JDBC driver vendor uses these types to describe how their product operates. Some JDBC driver types are better suited for some applications than others.

  There are  four types of JDBC drivers known as: 
  • JDBC-ODBC bridge plus ODBC driver, also called Type 1.
  • Native-API, partly Java driver, also called Type 2.
  • JDBC-Net, pure Java driver, also called Type 3.
  • Native-protocol, pure Java driver, also called Type 4.
Type 1 Driver- the JDBC-ODBC bridge

The JDBC type 1 driver, also known as the JDBC-ODBC bridge is a database driver implementation that employs the ODBC driver to connect to the database. The driver converts JDBC method calls into ODBC function calls. The bridge is usually used when there is no pure-Java driver available for a particular database.

The driver is implemented in the sun.jdbc.odbc.JdbcOdbcDriver class and comes with the Java 2 SDK, Standard Edition. The driver is platform-dependent as it makes use of ODBC which in turn depends on native libraries of the operating system. Also, using this driver has got other dependencies such as ODBC must be installed on the computer having the driver and the database which is being connected to must support an ODBC driver. Hence the use of this driver is discouraged if the alternative of a pure-Java driver is available.

Type 1 is the simplest of all but platform specific i.e only to Microsoft platform.

A JDBC-ODBC bridge provides JDBC API access via one or more ODBC drivers. Note that some ODBC native code and in many  cases native database client code must be loaded on each client machine that uses this type of driver. Hence, this kind of  driver is generally most appropriate when automatic installation and downloading of a Java technology application is not important. For information on the JDBC-ODBC bridge driver provided by Sun, see JDBC-ODBC Bridge Driver.

Type 1 drivers are "bridge" drivers. They use another technology such as Open Database Connectivity (ODBC) to communicate  with a database. This is an advantage because ODBC drivers exist for many Relational Database Management System (RDBMS) platforms. The Java Native Interface (JNI) is used to call ODBC functions from the JDBC driver.

A Type 1 driver needs to have the bridge driver installed and configured before JDBC can be used with it. This can be a serious drawback for a production application. Type 1 drivers cannot be used in an applet since applets cannot load native code.

  1.  Translates query obtained by JDBC into corresponding ODBC query, which is then handled by the ODBC driver. 
  2.  Sun provides a JDBC-ODBC Bridge driver. sun.jdbc.odbc.JdbcOdbcDriver. This driver is native code and not Java, and is closed
  3. Client -> JDBC Driver -> ODBC Driver -> Database
  4. There is some overhead associated with the translation work to go from JDBC to ODBC.

Almost any database for which ODBC driver is installed, can be accessed.

  1. Performance overhead since the calls have to go through the JDBC overhead bridge to the ODBC driver, then to the native database connectivity interface.
  2. The ODBC driver needs to be installed on the client machine.
  3. Considering the client-side software needed, this might not be suitable for applets.
Type 2 Driver - the Native-API Driver

The JDBC type 2 driver, also known as the Native-API driver is a database driver implementation that uses the client-side libraries of the database. The driver converts JDBC method calls into native calls of the database API.

The type 2 driver is not written entirely in Java as it interfaces with non-Java code that makes the final database calls.
The driver is compiled for use with the particular operating system. For platform interoperability, the Type 4 driver, being
a full-Java implementation, is preferred over this driver.

A native-API partly Java technology-enabled driver converts JDBC calls into calls on the client API for Oracle, Sybase, Informix, DB2, or other DBMS. Note that, like the bridge driver, this style of driver requires that some binary code be loaded on each client machine.

However the type 2 driver provides more functionality and performance than the type 1 driver as it does not have the overhead of the additional ODBC function calls.

Type 2 drivers use a native API to communicate with a database system. Java native methods are used to invoke the API functions that perform database operations. Type 2 drivers are generally faster than Type 1 drivers.

Type 2 drivers need native binary code installed and configured to work. A Type 2 driver also uses the JNI. You cannot use a Type 2 driver in an applet since applets cannot load native code. A Type 2 JDBC driver may require some Database Management System (DBMS) networking software to be installed.

The Developer Kit for Java JDBC driver is a Type 2 JDBC driver.

  1. This type of driver converts JDBC calls into calls to the client API for that database.
  2. Client -> JDBC Driver -> Vendor Client DB Library -> Database

Better performance than Type 1 since no jdbc to odbc translation is needed.

  1. The vendor client library needs to be installed on the client machine.
  2. Cannot be used in internet due the client side software needed.
  3. Not all databases give the client side library.
Type 3 driver - the Network-Protocol Driver

The JDBC type 3 driver, also known as the network-protocol driver is a database driver implementation which makes use of a middle-tier between the calling program and the database. The middle-tier (application server) converts JDBC calls directly or indirectly into the vendor-specific database protocol.
This differs from the type 4 driver in that the protocol conversion logic resides not at the client, but in the middle-tier. However, like type 4 drivers, the type 3 driver is written entirely in Java.
The same driver can be used for multiple databases. It depends on the number of databases the middleware has been configured to support. The type 3 driver is platform-independent as the platform-related differences are taken care by the middleware. Also, making use of the middleware provides additional advantages of security and firewall access.
A net-protocol fully Java technology-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 different databases. The specific protocol used depends on the vendor. In general, this is the most flexible JDBC API alternative. It is likely that all vendors of this solution will provide products suitable for Intranet use. In order for these products to also support Internet access they must handle the additional requirements for security, access through firewalls, etc., that the Web imposes. Several vendors are adding JDBC technology-based drivers to   their existing database middleware products.
These drivers use a networking protocol and middleware to communicate with a server. The server then translates the protocol to DBMS function calls specific to DBMS.
Type 3 JDBC drivers are the most flexible JDBC solution because they do not require any native binary code on the client. A Type 3 driver does not need any client installation.

  1. Follows a three tier communication approach.
  2. Can interface to multiple databases - Not vendor specific.
  3. The JDBC Client driver written in java, communicates with a middleware-net-server using a database independent  protocol, and then this net server translates this request into database commands for that database.
  4. Thus the client driver to middleware communication is database independent.
  5. Client -> JDBC Driver -> Middleware-Net Server -> Any Database
  1. Since the communication between client and the middleware server is database independent, there is no need for the vendor db library on the client machine. Also the client to middleware need'nt be changed for a new database.
  2. The Middleware Server (Can be a full fledged J2EE Application server) can provide typical middleware services like caching (connections, query results, and so on), load balancing, logging, auditing etc..
  3. eg. for the above include jdbc driver features in Weblogic.
  4. Can be used in internet since there is no client side software needed.
  5. At client side a single driver can handle any database.(It works provided the middlware supports that database!!)
  1. Requires database-specific coding to be done in the middle tier.
  2.  An extra layer added may result in a time-bottleneck. But typically this is overcome by providing efficient middleware
      services described above.
Type 4 - the Native-Protocol Driver

The JDBC type 4 driver, also known as the native-protocol driver is a database driver implementation that converts JDBC calls directly into the vendor-specific database protocol.

The type 4 driver is written completely in Java and is hence platform independent. It is installed inside the Java Virtual Machine of the client. It provides better performance over the type 1 and 2 drivers as it does not have the overhead of conversion of calls into ODBC or database API calls. Unlike the type 1 and 2 drivers, it does not need associated software to work.

A native-protocol fully Java technology-enabled driver converts JDBC technology calls into the network protocol used by DBMSs directly. This allows a direct call from the client machine to the DBMS server and is a practical solution for Intranet access. Since many of these protocols are proprietary the database vendors themselves will be the primary source for this style of driver. Several database vendors have these in progress.

As the database protocol is vendor-specific, separate drivers, usually vendor-supplied, need to be used to connect to the database.

A Type 4 driver uses Java to implement a DBMS vendor networking protocol. Since the protocols are usually proprietary, DBMS vendors are generally the only companies providing a Type 4 JDBC driver.

Type 4 drivers are all Java drivers. This means that there is no client installation or configuration. However, a Type 4 driver may not be suitable for some applications if the underlying protocol does not handle issues such as security and network connectivity well.

The IBM Toolbox for Java JDBC driver is a Type 4 JDBC driver, indicating that the API is a pure Java networking protocol driver.

  1. Type 4 drivers are entirely written in Java that communicate directly with a vendor's database through socket connections. No translation or middleware layers, are required, improving performance.
  2. The driver converts JDBC calls into the vendor-specific database protocol so that client applications can communicate directly with the database server.
  3. Completely implemented in Java to achieve platform independence.
  4. e.g include the widely used Oracle thin driver - oracle.jdbc.driver. OracleDriver which connect to jdbc:oracle:thin URL format.
  5. Client Machine -> Native protocol JDBC Driver -> Database server

These drivers don't translate the requests into db request to ODBC or pass it to client api for the db, nor do they need a middleware layer for request indirection. Thus the performance is considerably improved.


At client side, a separate driver is needed for each database.