RKTechGame | Executing Queries and Updates in JDBC

JDBC me SQL Queries aur Updates Execute Karna

JDBC me SQL queries aur updates chalane ke liye commonly do methods ka use hota hai:

• executeQuery(String sql): Ye method SELECT queries chalata hai jiska output hota hai data rows yani ResultSet. Ye tab use karte hain jab data fetch karna ho.
• executeUpdate(String sql): Ye method INSERT, UPDATE, DELETE jaise statements chalata hai jo database me data modify karte hain. Ye affected rows ka count return karta hai.

Example: executeQuery() aur executeUpdate() ka Use

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

public class JdbcQueryUpdateExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase?serverTimezone=UTC";
        String user = "root";
        String password = "yourpassword";

        try (Connection con = DriverManager.getConnection(url, user, password);
             Statement stmt = con.createStatement()) {

            // Insert record using executeUpdate()
            String insert = "INSERT INTO employees (id, name, email) VALUES (1, 'Amit Sharma', 'amit@example.com')";
            int insertCount = stmt.executeUpdate(insert);
            System.out.println("Number of rows inserted: " + insertCount);

            // Update record using executeUpdate()
            String update = "UPDATE employees SET email = 'amit.sharma@example.com' WHERE id = 1";
            int updateCount = stmt.executeUpdate(update);
            System.out.println("Number of rows updated: " + updateCount);

            // Select records using executeQuery()
            String select = "SELECT id, name, email FROM employees";
            ResultSet rs = stmt.executeQuery(select);

            System.out.println("Employee Records:");
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String email = rs.getString("email");
                System.out.println("ID: " + id + ", Name: " + name + ", Email: " + email);
            }
            rs.close();

        } catch (SQLException e) {
            System.err.println("Database error: " + e.getMessage());
        }
    }
}

Is program me:

• Pehle rows insert kiya gaye `executeUpdate()` se.
• Phir ek row ko update kiya.
• Aur finally sari rows query karke print ki gayi.