Introduction to Jdbc

The JDBC(Java Database Connectivity) API(Collection of classes and interfaces) is a technique through which we connect our program to the database smoothly. Java is one of the best languages that provides a connection through to the database smoothly, in comparison to other language.

Java Program ||--->JDBC Api ||--->Driver||--->||Database Source

            Figure 1: Description of the working of Jdbc

Steps of Jdbc for connecting the database  

1. Loading the Jdbc driver.
2. Connection to the Dbms.
3. Creating and executing a statement.
4. Processing data returned by the Dbms
5. Close the connection with the Dbms.

We have to import the sql package, which resides in the java .lang package for performing these steps. After this step we have to write our code for connecting to any database.

• Loading Jdbc Driver: In this step, we load the driver class at runtime which implements the Driver interface. In Java we use a class known as Class for loading any class at runtime .forName(Driver name in String) is the static method of class, Class is used to load any driver class at runtime. The return type of this method is an object of class ,Class.

Syntax:Class.forName(sun.jdbc.odbc.JdbcOdbcDriver);

The above line is used for loading any driver class at runtime. We generally do not catch the value (Object of class,Class) returned by this method.   
 

•  Connection to the Dbms: In the second step we have to create a connection with the database. For this we use the DriverManager class. There is a static method,getConnection("url","user name","password")  of DriverManager class.It takes three string type arguments,and returns object of Connection.   

   Syntax:  Connection con = DriverManager.getConnection("jdbc:odbc:mydsn","system","tiger"); 
   

• Creating and executing a statement: Using a Connection we create statement by the method createStatement() and get the object of Statement.

  Syntax:Statement s=con.createStatement();
   

• Processing data returned by Dbms: According to our query we use the data returned by Dbms.

In this way, we connect a java program using the Jdbc.

Simple program for creating connection in Java

import java.sql.*;
class CreateConnection
{
    public static void main(String s[])
    {
        try
        {
            //Loading the Driver
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            //Creating the Connection
            Connection con = DriverManager.getConnection("jdbc:odbc:mydsn","System","tiger");
            if(con!=null)
            {
                System.out.println("Connection Successfull");
            }
            else
            {
                System.out.println("Connection could not be established");
            }
            //closing the connection
            conn.close();
        }
        catch(SqlException e)
        {
            System.out.println("Exception occured"+ e);
        }
    }
}

After compilation and execution of above program we get the output as:

Thank You.....