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JDBC FAQ part3

4: What is JDBC and What are the steps to write a JDBC application?
      The process of interacting with the database from a java application is called as JDBC(Java Database Connectivity)
To interact with the database from a java application we will use the following five   steps.
  1. load and register the driver.
  2. Establish a connection between java application and the database.
  3. prepare either statement object or PreparedStatement object or CallebleStatement object as per the application requirements.
  4. write and execute the SQL queries.
  5. terminate the connection which we have established.
5:  How to load a JDBC driver? 
    • In general sun Microsystems  has provided Driver interface for this all the database vendors has provided their own implementation.
    • If we want to use the database vendor provided Driver implementation to our JDBC application, first we need to make the availability of the respective Driver’s   .class file to JVM, for this, we need to set classpath environment variable to the location where we have the driver implementation.
    • Sun Microsystems is also provided an implementation to the Driver interface in the form of JdbcOdbcDriver class as part of the java software.
    • If we want to use JdbcOdbcDriver in our JDBC applications no need to set classpath environment variable. Why because it was already available in the java software’s pre-defined library.
    • JdbcOdbcDriver internally depends on the Microsoft product Odbc driver. If we want to use the JdbcOdbcDriver in our JDBC applications first we must configure Odbc driver, for this, we will use the following path.
Start/ conrlol panel / performance and maintenance / administrative tools / data source(Odbc)/ user dsn / click on Add / select microsofr Odbc for oracle / finish / provide data source name only / click on ok / ok.
  • To load the driver’s class bytecode to the memory we will use the following method.
Public void forName(String class name)
Eg:    Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
      Where forName() is a static method, which can be used to load the respective driver class bytecode to the memory.
  • Each and every driver class has already a static block at the time of loading the respective driver class bytecode to the memory automatically the available static block could be executed, by this  DriverMadoeer.registerDriver(….) method will be executed as part of the static block.
  • By the execution of the registerDriver(….) method automatically the specified driver will be registered to the JDBC application.
  • If you want to design any JDBC application, we need to use some pre-defined library, which was provided by the JDBC API in the form of java.sql package, that’s why we need to import the java.sql package in our JDBC application.
Note:-   The best alternative for Class.forName(..) is
 DriverMadoere.registerDriver(new sun.jdbc.odbc.JdbcOdbcDriver());
  To register the driver.


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