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Up Date Records

This chapter provides an example on how to update records in a table using JDBC application. Before executing the following example, make sure you have the following in place:
  • To execute the following example you can replace the username and password with your actual user name and password.
  • Your MySQL or whatever database you are using, is up and running.
Required Steps

The following steps are 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 update records in a table. This Query makes use of IN and WHERE clause to update conditional records.
  • Clean up the environment: Requires explicitly closing all database resources versus relying on the JVM's garbage collection.
Sample Code

Copy and paste the following example in, 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;
//STEP 2: Register 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("Creating statement...");
stmt = conn.createStatement();
String sql = "UPDATE Registration " +
"SET age = 30 WHERE id in (100, 101)";
// Now you can extract all the records
// to see the updated records
sql = "SELECT id, first, last, age FROM Registration";
ResultSet rs = stmt.executeQuery(sql);
//Retrieve by column name
int id = rs.getInt("id");
int age = rs.getInt("age");
String first = rs.getString("first");
String last = rs.getString("last");
//Display values
System.out.print("ID: " + id);
System.out.print(", Age: " + age);
System.out.print(", First: " + first);
System.out.println(", Last: " + last);
}catch(SQLException se){
//Handle errors for JDBC
}catch(Exception e){
//Handle errors for Class.forName
//finally block used to close resources
}catch(SQLException se){
}// do nothing
}catch(SQLException se){
}//end finally try
}//end try
}//end main
}//end JDBCExample

Now, let us compile the above example as follows:


When you run JDBCExample, it produces the following result:

C:\>java JDBCExample
Connecting to a selected database...
Connected database successfully...
Creating statement...
ID: 100, Age: 30, First: Zara, Last: Ali
ID: 101, Age: 30, First: Mahnaz, Last: Fatma
ID: 102, Age: 30, First: Zaid, Last: Khan
ID: 103, Age: 28, First: Sumit, Last: Mittal
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