Delete a Column from a Database Table

In this section, we are going to learn how to delete a column from a database table

Delete a Column from a Database Table

Delete a Column from a Database Table

     

In this section, we are going to learn how to delete a column from a database table. We are not going to create a new table into, and we are expecting that you can make a table yourself. We are using the already created table in the specific database. Now if we want to delete a column from a database table then we have been provided with the  database query by which we can do this task very easily. See detailed information  below:

Description of program:

The thing which we are going to perform first is to establish the connection by using the JDBC driver. If any problem is created at the time of connection then it shows java.lang.ClassNotFoundException exception. After establishing the connection gives a table name and column name which you want to delete. When column gets deleted then it shows "Column is deleted successfully". But if SQL statement doesn't get executed then an exception is thrown and displays a message: "Table or column is not found!".

Description of code:

ALTER TABLE  table_name  DROP   col_name;
This code is used to delete the column form a database table 
  table_name: This is a table name in which you want to any editing.
  col_name: This is a column name which have to deleted.

Here is the code of program:

import java.io.*;
import java.sql.*;

public class DeleteColumn{
  public static void main(String[] args) {
  System.out.println("Delete columns example!");
  Connection con = null;
  try{
  Class.forName("com.mysql.jdbc.Driver");
  con = DriverManager.getConnection
("jdbc:mysql://localhost:3306/jdbctutorial","root","root");
  try{
  Statement st = con.createStatement();
  BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
  System.out.println("Enter table name: ");
  String table = bf.readLine();
  System.out.println("Enter column name: ");
  String col = bf.readLine();
  st.executeUpdate("ALTER TABLE "+table+" DROP "+col);
  System.out.println("Column is deleted successfully!");
  }
  catch (SQLException s){
  System.out.println("Table or column is not found!");
  }
  }
  catch (Exception e){
  e.printStackTrace();
  }
  }
} 

Database Table: Student Table

Stu_roll Stu_name Stu_sub Stu_marks
100 vinod computer 95
101 raju math 89
102 ranjan bio 80
103 Aman phy 85

Output of program:

C:\vinod\jdbc\jdbc\jdbc-mysql>javac DeleteColumn.java

C:\vinod\jdbc\jdbc\jdbc-mysql>java DeleteColumn
Delete columns example!
Enter table name:
Student
Enter column name:
Stu_marks
Column is deleted successfully!

After deleting a column: 

Student Table

Stu_roll Stu_name Stu_sub
100 vinod computer
101 raju math
102 ranjan bio
103 Aman phy

Download this example.

Tutorials

  1. Mapping MySQL Data Types in Java
  2. Connecting to a MySQL Database in Java
  3. Creating a Database in MySQL
  4. Creating a Database Table
  5. Creating a MySQL Database Table to store Java Types
  6. Description of Database Table
  7. Deleting a Table from Database
  8. Retrieving Tables from a Database
  9. Inserting values in MySQL database table
  10. Retrieving All Rows from a Database Table
  11. Adding a New Column Name in Database Table
  12. Change Column Name of a Table
  13. Make Unique Column in Database Table
  14. Remove Unique Column in Database Table
  15. Arrange a Column of Database Table
  16. Arrange a Column of Database Table
  17. Sum of Column in a Database Table
  18. Deleting All Rows from a Database Table
  19. Delete a Specific Row from a Database Table
  20. Delete a Column from a Database Table
  21. Join tables in the specific database
  22. Join tables with the NATURAL LEFT JOIN operation
  23. Join tables with the NATURAL RIGHT JOIN operation
  24. Cross Join Tables in a Specific Database
  25. Prepared Statement Set Object
  26. Statement Batch Update
  27. Prepared Statement With Batch Update
  28. Select Records Using Prepared Statement
  29. Update Records using Prepared Statement
  30. Inserting Records using the Prepared Statement
  31. Count Records using the Prepared Statement
  32. Deleting Records using the Prepared Statement
  33. Using the Prepared Statement Twice
  34. Set Data Types by using Prepared Statement
  35. Set byte, short and long data types by using the Prepared Statement
  36. Prepared Statement Set Big Decimal
  37. Set Date by using the Prepared Statement
  38. Set Time by using the Prepared Statement
  39. Set Timestamp by using the Prepared Statement
  40. Copy Table in a MySQL Database