JDBC

JDBC ( Java Data-Base Connectivity ) - A platform-neutral API for connecting to DBs and supplying low-level support for SQL functionality. Emphasis is on how to find the data and not what to find.

SQL ( Structured Query Language ) - A non-procedural language for interaction with an RDBMS, developed by IBM in 70s-80s. DDL (Data Definition Lang.) Subset of SQL commands for defining tables, columns and for adding and removing table entries, includes CREATE, DROP, ALTER commands. DML (Data Maintenance Lang.) Subset of SQL used to manipulate the data in tables using INSERT, DELETE and UPDATE. DQL (Data Query Lang.) Used to retrieve data from tables using SELECT, etc.

import java.sql.*;
import java.io.*;

public class oracle
{
   public static void main(String args[])
   {
    try{
//  1. Load the Driver 
        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
//  2. Create Connection 
        Connection con = DriverManager.getConnection("jdbc:odbc:sam","euser","pwd");
//  3. Create Statement 
        Statement stmt = con.createStatement();
//  4. Execute SQL Query 
        ResultSet rs = stmt.executeQuery("SELECT ename, sal FROM emp"):
//  5. Iterate Resultset 
        boolean flag = rs.next();
        while( flag )
          {
           System.out.println(rs.getString("ename")+rs.getInt("sal");
           flag = rs.next();
          }
        }
     catch(Exception e) { }
    }
}