Adding a New Column Name in Database Table
In this jdbc tutorial program we are going to learn about adding a new column in
database table. Sometimes it happens that we have created a table and forgets to
add some important column name into it. Later while retrieving the data from
that table we come to know that the table doesn't contains that particular
column we are searching for. So there is no need to get panic. We have the
solution for this, we are describing it with the help of the simple example. Brief description given below:
Description of program:
Firstly we need to create a connection with the
help of JDBC driver for connecting to the MySQL database. Remember,
in this program we are going to add columns to an existing database table. After
establishing the connection, it takes table name, column name and it's data type
and at last add a new column in the table. If the column gets inserted or added in the table then
it shows
"Query OK, n rows affected" otherwise it will displays a
message "Table
or column or data type is not found!".
Description of code:
ALTER TABLE
table_name ADD
col_name data_type;
Above code is used for adding a new column in the database table and takes
appropriate attributes:
table_name: This is a table
name in which you want to add a new column name.
col_name: It is a name of the
column that you want to add in a table.
data_type: This is a data type
of new column.
Here is the code of program:
import java.io.*;
import java.sql.*;
public class AddColumn{
public static void main(String[] args) {
System.out.println("Adding new column in table 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();
System.out.println("Enter data type:");
String type = bf.readLine();
int n = st.executeUpdate("ALTER TABLE "+table+" ADD "+col+" "+type);
System.out.println("Query OK, "+n+" rows affected");
}
catch (SQLException s){
System.out.println("Tabel or column or data type is not found!");
}
}
catch (Exception e){
e.printStackTrace();
}
}
}
|
Database Table: Student Table
| Stu_id |
Stu_name |
Stu_sub |
| 100 |
vinod |
computer |
| 101 |
raju |
math |
| 102 |
ranjan |
bio |
| 103 |
Aman |
phy |
Output of program:
C:\vinod\jdbc\jdbc\jdbc-mysql>javac AddColumn.java
C:\vinod\jdbc\jdbc\jdbc-mysql>java AddColumn
Adding new column in table example!
Enter table name:
Student
Enter column name:
Stu_marks
Enter data type:
integer
Query OK, 4 rows affected |
After adding a new column: Student Table
| Stu_idl |
Stu_name |
Stu_sub |
Stu_marks |
| 100 |
vinod |
computer |
NULL |
| 101 |
raju |
math |
NULL |
| 102 |
ranjan |
bio |
NULL |
| 103 |
Aman |
phy |
NULL |
Download this example.
|
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