Java applications cannot directly communicate with a database to submit and retrieve the results of queries.this is because dbms/rdbms can understand only SQL statements and not java language statements .hence you need a mechanism to transalate java statements to SQL statements.
JDBC API uses a driver to address these issues .JDBC API takes care of converting java commands to generic SQL statements .
There are several categories of jdbc drivers provided by different database vendors .They are
1.JDBC-ODBC bridge driver:there are several DBMS/RDBMS, such as MS acess and SQL server that contain the ODBC driver embedded into them.since the ODBC API is written in the Clanguage and makes use of ponters and other constructs that java does not support ,a java program cannot directly communicate with an ODBC driver.The JDBC-ODBC bridge driver transalates the JDBC API to the ODBC API
2.Native API partly java driver: some DBMS/RDBMS,such as DB2and Informix,contail a JDBC driver supplied by the database vendor.JDBC drivers consist of classes that the JDBC API can invoke directly.
3.NATIVE protocal pure java driver/JDBC-net pure java driver: these drivers are used to connect a client application or applet to a database over a TCP/IP connection
4.JDBC DRIVer MANAGER
the functions are to maintain a list of drivers created for different databases and connect a java apllication to the appropriate driver specified in a java program
5.JDBC-ODBC Bridge
as apart of JDbc ,sun microsysyems provides a driver to acess ODBC data sources from JDBC.This driver s called JDBC-ODBC bridge.
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