Update a Column in a Table using Java JDBC

Introduction

Updating a column in a database table is a relatively frequent activity in software development. Java Database Connectivity (also known as JDBC API), which serves as a link between Java programmers and databases like MySQL, may be used to carry out this task in Java. Using the JDBC API, we may establish a connection to the database, get data from tables, and carry out a number of tasks, including altering columns.

We will talk about how to update a column in a table using Java JDBC. We will start by make a connection to the database and then we will fetch data from a demo table in our SQL. At last, we will explain how to update a particular column in the table by SQL update statements.

We make a database connection using java JDBC

Here we will learn about how to create database connection in java JDBC.

Example

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class conncreate {
   public static void main(String args []) 
   {
      String link = "jdbc:mysql://localhost:3308/dbtest";
      String username = "PAPAI";
      String password = "pass";
      try 
      {         
         Class.forName("com.mysql.jdbc.Driver");
         Connection connection = DriverManager.getConnection(link, username, password);
         System.out.println("Database is successfully connected!");
         connection.close();
      } catch (ClassNotFoundException e) {
         System.out.println("Driver not found!");
         e.printStackTrace();
      } catch (SQLException e) {
         System.out.println("Error connecting to the database!");
         e.printStackTrace();
      }
   }
}

For this we have imported some important packages in our java program. These important packages are java.sql.Connection;

java.sql.DriverManager;
java.sql.SQLException;

Now we have defined a class named conncreate and inside this class we have called the main function. Inside this function we have set the SQL user name and password by writing String link = "jdbc:mysql://localhost:3308/dbtest";

Now we have set the user name "PAPAI" and password "pass". After that we have create a connection object by writing Connection connection = DriverManager.getConnection(link, username, password);

Lastly we have closed the data base connection by calling the function named connection.close (). The output is successfully executed.

Use JDBC to fetch data from database:

Here we will learn about how to fetch the sample table using JDBC.

Example

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statmemt;
public class tablestud
{
   public static void main(String args [])
   {
      String link = "jdbc:mysql://localhost:3308/dbtest";
      String username = "PAPAI";
      String password = "pass";
      try {
         // Load the JDBC driver
         Class.forName("com.mysql.jdbc.Driver");
         // Create a connection object
         Connection connection = DriverManager.getConnection(link, username, password);
         Statement statement = connection.createStatement();
         // Execute the SQL query to fetch the table
         String query = "SELECT * FROM studs";
         ResultSet resultSet = statement.executeQuery(query);
         while (resultSet.next()) {
            String name = resultSet.getString("name");
            int age = resultSet.getInt("age");
            System.out.println("Name: " + name + ", Age: " + age);
         }
         resultSet.close();
         statement.close();
         connection.close();
      } catch (ClassNotFoundException e) {
         System.out.println("Driver not found!");
         e.printStackTrace();
      } catch (SQLException e) {
         System.out.println("cannot connect to database");
         e.printStackTrace();
      }
   }
}

Output

Name: Ram Age: 20
Name: Madhumita Age: 21
Name: Laxman, Age: 19
Name: Priya, Age: 22

For this we have imported some important packages in our java program. These important packages are:

java.sql.Connection;
java.sql.DriverManager;
java.sql.ResultSet;
java.sql.SQLException;
java.sql.Statement;

Now we have defined a class named tablestud and inside this class we will call the main function. Inside this function we have set the sql user name and password by writing:

String username = "PAPAI";
String password = "pass";

Then we have Loaded the JDBC driver and create a connection object by writing

Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection(link, username, password);

Now we have Created a statement object by writing

Statement statement = connection.createStatement();

After that we have Executed the SQL query to fetch the table by writing SQL query.

String query = "SELECT * FROM studs";

Then we have Retrieved the column values and close the connection.

Update a Column in a Table using Java JDBC:

Here we will learn about how to Update a Column in a Table using Java JDBC.

Example

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class UpdateColumn
{
   public static void main(String args []) 
   {
      String link = "jdbc:mysql://localhost:3308/dbtest";
      String username = "PAPAI";
      String password = "pass";
      try {
         Class.forName("com.mysql.jdbc.Driver");
                  Connection connection = DriverManager.getConnection(link, username, password);
         Statement statement = connection.createStatement();
         // Update a Column in a Table
         String columnUpdate = "ALTER TABLE studs RENAME COLUMN name TO ClassXI_students ";
         // Run the update statement
         statement.executeUpdate(columnUpdate);
         System.out.println("Column in a Table updated successfully!");
         statement.close();
         connection.close();
      } catch (ClassNotFoundException e) {
         System.out.println("Driver not found!");
         e.printStackTrace();
      } catch (SQLException e) {
         System.out.println("Cannot connect to database!");
         e.printStackTrace();
      }
   }
}

Output

Column in a Table updated successfully!
** database output **
> DESCRIBE studs;
id 	ClassXI_students		age
1	    Ram				    20
2	    Madhumita		   	21
3	    Laxman			    19
4	    Priya				22

For this we have imported some important packages in our java program. These important packages are

java.sql.Connection;
java.sql.DriverManager;
java.sql.SQLException;
java.sql.Statement;

Now we have defined a class named UpdateColumn and inside this class we have called the main () function. Inside this function we have l set the SQL user name and password.

Then we have Loaded the JDBC driver and create a connection object by writing Class.forName("com.mysql.jdbc.Driver"); Connection connection = DriverManager.getConnection(link, username, password);. Now we have run the update statement by writing statement.executeUpdate(columnUpdate).

Then we have Retrieved the column values and close the connection by calling a standard function named connection.close() and executed the output.

Conclusion

Here we knew the concept about how to update a column in a table using java JDBC. Knowing this concept, we will easily handle the updating column in a table in an efficient manner such that user can easily manipulate data or information in the table easily. It is an important concept under the JDBC connection in SQL.