In this example we shall show you how to update a Table row. To update a Table row one should perform the following steps:
- Load the JDBC driver, using the
forName(String className)API method of the Class. In this example we use the MySQL JDBC driver. - Create a Connection to the database. Invoke the
getConnection(String url, String user, String password)API method of the DriverManager to create the connection. - Create a Statement, using the
createStatement()API method of the Connection. - Invoke the
executeUpdate(String sql)API method to update a specific column. It returns the number of rows updated. - For updates that are executed frequently we should use the PreparedStatement, using the
prepareStatement(String sql)API method of the Connection. For example, to update 10 rows invoke thesetString(int parameterIndex, String x)of the PreparedStatement, setting the values to the first and second parameter of each one of the 10 rows. Then invoke theexecuteUpdate()API method to execute the update,
as described in the code snippet below.
package com.javacodegeeks.snippets.core;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
public class UpdateRowsExample {
public static void main(String[] args) {
Connection connection = null;
try {
// Load the MySQL JDBC driver
String driverName = "com.mysql.jdbc.Driver";
Class.forName(driverName);
// Create a connection to the database
String serverName = "localhost";
String schema = "test";
String url = "jdbc:mysql://" + serverName + "/" + schema;
String username = "username";
String password = "password";
connection = DriverManager.getConnection(url, username, password);
System.out.println("Successfully Connected to the database!");
} catch (ClassNotFoundException e) {
System.out.println("Could not find the database driver " + e.getMessage());
} catch (SQLException e) {
System.out.println("Could not connect to the database " + e.getMessage());
}
try {
/*
* For updates that are not executed frequently we should use the statement API.
* updateCount contains the number of updated rows
*/
Statement statement = connection.createStatement();
int updateCount = statement.executeUpdate("UPDATE test_table SET test_col='new_test_value' WHERE test_col = 'test_value'");
System.out.println("Updated test_value successfully : " + updateCount );
/*
* For updates that are executed frequently we should
* use the prepared statement API.
*/
PreparedStatement preparedStatement = connection.prepareStatement("UPDATE test_table SET test_col=? WHERE test_col = ?");
// update 10 rows
for (int i=0; i<10; i++) {
preparedStatement.setString(1, "new_test_value_"+i);
preparedStatement.setString(2, "test_value_"+i);
// updateCount contains the number of updated rows
updateCount = preparedStatement.executeUpdate();
System.out.println("Updated test_value_" + i +" successfully : " + updateCount );
}
} catch (SQLException e) {
System.out.println("Could not update data to the database " + e.getMessage());
}
}
}
Example Output:
Successfully Connected to the database!
Updated test_value successfully : 1
Updated test_value_0 successfully : 1
Updated test_value_1 successfully : 1
Updated test_value_2 successfully : 1
Updated test_value_3 successfully : 1
Updated test_value_4 successfully : 1
Updated test_value_5 successfully : 1
Updated test_value_6 successfully : 1
Updated test_value_7 successfully : 1
Updated test_value_8 successfully : 1
Updated test_value_9 successfully : 1
This was an example of how to update a Table row in Java.
