JAVA-DATABASE

1. Load and Register the Driver Class

Class.forName("com.mysql.cj.jdbc.Driver");

2. Establish Connection Between Java Application and Database

'DriverManager.getConnection()'

`import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException;

public class DBConnection { public static void main(String[] args) { String url = "jdbc:mysql://localhost:3306/your_database"; String user = "your_username"; String password = "your_password";

    tyr(Connection conn = DriverManager.getConnection(url, user, passwordl)) {
       System.out.println("Database connected successfully!");
    } catch (SQLException e) {
        e.printStackTrace();
      }
}

}`

3.Create a Statement Object

'Statement'

`import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException;

import java.sql.Statement;

public class DBConnection { public static void main(String[] args) { String url = "jdbc:mysql://localhost:3306/your_database"; String user = "your_username"; String password = "your_password";

    tyr(Connection conn = DriverManager.getConnection(url, user, passwordl); Statement stmt = conn.createStatement()) {
       System.out.println("Database object created!");
    } catch (SQLException e) {
        e.printStackTrace();
      }
}

}`

4. Prepare, Send, and Execute SQL Queries

Use executeUpdate() for INSERT, UPDATE, and DELETE queries. Use executeQuery() for SELECT queries.

Example: Insert Data String sql = "INSERT INTO users (name, email) VALUES ('Umugisha', 'umugisha@gmail.com')"; stmt.executeUpdate(sql); System.out.println("Data inserted successfully!");

Example: Retrieve Data String sql = "SELECT * FROM users"; ResultSet rs = stmt.executeQuery(sql);

5. Process Results from ResultSet

If executing a SELECT query, process results using ResultSet.

`import java.sql.*;

public class RetrieveData { public static void main(String[] args) { String url = "jdbc:mysql://localhost:3306/your_database"; String user = "your_username"; String password = "your_password";

    try (Connection conn = DriverManager.getConnection(url, user, password);
         Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery("SELECT * FROM users")) {

        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);
        }

    } catch (SQLException e) {
        e.printStackTrace();
    }
}

}`

6. Close Connection

. Using try-with-resources (best practice, auto-closes resources): try (Connection conn = DriverManager.getConnection(url, user, password); Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery("SELECT * FROM users")) { . Manually closing resources: rs.close(); stmt.close(); conn.close();

Summary of Steps

✅ Load Driver (Not always required in modern JDBC) ✅ Establish Connection ✅ Create Statement Object ✅ Prepare, Send, and Execute SQL Queries ✅ Process Results ✅ Close Connection