JDBC Drop Tables Example ~ Java Tutorials by Experts

Tuesday, May 21, 2013

JDBC Drop Tables Example

naresh JDBC Drop Tables Example No comments

This tutorial provides an example on how to delete a table using JDBC application. Before executing following example, make sure you have the following in place:

To execute the following example you can replace username and password with your actual user name and password.
Your MySQL or whatever database you are using is up and running.

NOTE: This is a serious operation and you have to make a firm decision before proceeding to delete a table because everything you have in your table would be lost.

Required Steps:

There are following steps required to create a new Database using JDBC application:

Import the packages: Requires that you include the packages containing the JDBC classes needed for database programming. Most often, using import java.sql.* will suffice.
Register the JDBC driver: Requires that you initialize a driver so you can open a communications channel with the database.
Open a connection: Requires using the DriverManager.getConnection() method to create a Connection object, which represents a physical connection with a database server.
Execute a query: Requires using an object of type Statement for building and submitting an SQL statement to drop a table in a seleted database.
Clean up the environment . Requires explicitly closing all database resources versus relying on the JVM's garbage collection.

Sample Code:

Copy and past following example in JDBCExample.java, compile and run as follows:

//STEP 1. Import required packages
import java.sql.*;

public class JDBCExample {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
   static final String DB_URL = "jdbc:mysql://localhost/STUDENTS";

   //  Database credentials
   static final String USER = "username";
   static final String PASS = "password";
   
   public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   try{
      //STEP 2: Register JDBC driver
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to a selected database...");
      conn = DriverManager.getConnection(DB_URL, USER, PASS);
      System.out.println("Connected database successfully...");
      
      //STEP 4: Execute a query
      System.out.println("Deleting table in given database...");
      stmt = conn.createStatement();
      
      String sql = "DROP TABLE REGISTRATION ";
 
      stmt.executeUpdate(sql);
      System.out.println("Table  deleted in given database...");
   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            conn.close();
      }catch(SQLException se){
      }// do nothing
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");
}//end main
}//end JDBCExample

Now let us compile above example as follows:

C:\>javac JDBCExample.java
C:\>

When you run JDBCExample, it produces following result:

C:\>java JDBCExample
Connecting to a selected database...
Connected database successfully...
Deleting table in given database...
Table  deleted in given database...
Goodbye!
C:\>

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Tuesday, May 21, 2013