# Java JDBC ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1711529769816/dcc15676-3be5-40da-acfa-626c0d22cc6c.png align="center") ```java package jdbc; import java.sql.*; public class PostgreSQLCRUDExample { // JDBC URL, username, and password static final String JDBC_URL = "jdbc:postgresql://localhost:5432/practicedb"; static final String USERNAME = "postgres"; static final String PASSWORD = "123456"; public static void main(String[] args) { Connection connection = null; try { // Registering the JDBC driver Class.forName("org.postgresql.Driver"); // Establishing the connection connection = DriverManager.getConnection(JDBC_URL, USERNAME, PASSWORD); // CREATE operation example // createRecord(connection, "John", 30); // READ operation example readRecords(connection); // UPDATE operation example // updateRecord(connection, "John", 35); // DELETE operation example // deleteRecord(connection, "John"); // Closing the connection connection.close(); } catch (ClassNotFoundException e) { System.out.println("PostgreSQL JDBC driver not found."); e.printStackTrace(); } catch (SQLException e) { System.out.println("Failed to connect to the PostgreSQL database."); e.printStackTrace(); } finally { try { if (connection != null) { connection.close(); } } catch (SQLException e) { e.printStackTrace(); } } } // Method to create a record private static void createRecord(Connection connection, String name, int age) throws SQLException { String insertSQL = "INSERT INTO example_table (name, age) VALUES (?, ?)"; PreparedStatement preparedStatement = connection.prepareStatement(insertSQL); preparedStatement.setString(1, name); preparedStatement.setInt(2, age); preparedStatement.executeUpdate(); System.out.println("Record created successfully."); preparedStatement.close(); } // Method to read records private static void readRecords(Connection connection) throws SQLException { String selectSQL = "SELECT emp_id, emp_name, dept_name, salary FROM \"30daysSQLQueryChallenge\".employee;"; Statement statement = connection.createStatement(); ResultSet resultSet = statement.executeQuery(selectSQL); while (resultSet.next()) { int emp_id = resultSet.getInt("emp_id"); String emp_name = resultSet.getString("emp_name"); String dept_name = resultSet.getString("dept_name"); int salary = resultSet.getInt("salary"); System.out.println("emp_id: " + emp_id + ", emp_name: " + emp_name + ",dept_name:" + dept_name + "salary: " + salary); } resultSet.close(); statement.close(); } // Method to update a record private static void updateRecord(Connection connection, String name, int newAge) throws SQLException { String updateSQL = "UPDATE example_table SET age = ? WHERE name = ?"; PreparedStatement preparedStatement = connection.prepareStatement(updateSQL); preparedStatement.setInt(1, newAge); preparedStatement.setString(2, name); int rowsAffected = preparedStatement.executeUpdate(); if (rowsAffected > 0) { System.out.println("Record updated successfully."); } else { System.out.println("Record not found for update."); } preparedStatement.close(); } // Method to delete a record private static void deleteRecord(Connection connection, String name) throws SQLException { String deleteSQL = "DELETE FROM example_table WHERE name = ?"; PreparedStatement preparedStatement = connection.prepareStatement(deleteSQL); preparedStatement.setString(1, name); int rowsAffected = preparedStatement.executeUpdate(); if (rowsAffected > 0) { System.out.println("Record deleted successfully."); } else { System.out.println("Record not found for delete."); } preparedStatement.close(); } } ```