To insert rows into a database using JDBC, you typically use the executeUpdate(String sql) method of a Statement or PreparedStatement object.

Here are the two primary ways to do it:

1. Using PreparedStatement (Recommended)

This is the standard approach because it prevents SQL Injection and is more efficient for repeated inserts.

package org.kodejava.jdbc;

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

public class InsertRecordExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/kodejava";
        String user = "root";
        String password = "password";

        String sql = "INSERT INTO users (username, email) VALUES (?, ?)";

        try (Connection conn = DriverManager.getConnection(url, user, password);
             PreparedStatement pstmt = conn.prepareStatement(sql)) {

            // Set the values for the placeholders (?)
            pstmt.setString(1, "john_doe");
            pstmt.setString(2, "[email protected]");

            // executeUpdate returns the number of rows affected
            int rowsInserted = pstmt.executeUpdate();
            if (rowsInserted > 0) {
                System.out.println("A new user was inserted successfully!");
            }

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

2. Using Statement

Use this only for simple, static SQL queries where no user input is involved.

// ... existing code ...
    try (Connection conn = DriverManager.getConnection(url, user, password);
         Statement stmt = conn.createStatement()) {

        String sql = "INSERT INTO users (username, email) VALUES ('jane_doe', '[email protected]')";
        int rows = stmt.executeUpdate(sql);

        System.out.println("Rows affected: " + rows);
    } catch (SQLException e) {
        e.printStackTrace();
    }
// ... existing code ...

Key Takeaways:

• executeUpdate(): Unlike executeQuery() (which returns a ResultSet), executeUpdate() returns an int representing how many rows were added, changed, or deleted.
• Try-with-resources: Always wrap your Connection, Statement, or PreparedStatement in a try-with-resources block to ensure they are closed automatically, even if an error occurs.
• Placeholders: In a PreparedStatement, indices for ? parameters start at 1.