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 languages.
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.
connection in java
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 an 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 the 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
  1. import java.sql.*;  
  2. class CreateConnection  
  3. {  
  4.     public static void main(String s[])  
  5.     {  
  6.         try  
  7.         {  
  8.             //Loading the Driver  
  9.             Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");  
  10.             //Creating the Connection  
  11.             Connection con = DriverManager.getConnection("jdbc:odbc:mydsn","System","tiger");  
  12.             if(con!=null)  
  13.             {  
  14.                 System.out.println("Connection Successfull");  
  15.             }  
  16.             else  
  17.             {  
  18.                 System.out.println("Connection could not be established");  
  19.             }  
  20.             //closing the connection  
  21.             conn.close();  
  22.         }  
  23.         catch(SqlException e)  
  24.         {  
  25.             System.out.println("Exception occured"+ e);  
  26.         }  
  27.     }  
  28. }  
After compilation and execution of above program we get the output as:
Thank You.....