Chapter 23: CRUD: Create in JavaScript

Insert rows with auto-increment IDs. In this chapter, you will learn crud: create in depth with JavaScript code examples, explanations, and best practices.

Overview

This chapter covers crud: create for Kungfu.js developers using JavaScript. We will start with the basics, move through practical examples, and end with advanced techniques and common pitfalls.

Why This Matters

Understanding crud: create is essential because it is a core part of building web applications. Every real-world app needs to handle insert rows with auto-increment ids. Skipping this chapter would leave a gap in your knowledge that would cause problems later.

Code Example

Here is how to work with databases in JavaScript:

let user = User {
    id: 0,  // auto-assigned by database
    email: "alice@example.com".into(),
    password: "secure_password".into(),
    computed_field: String::new(),
};
let created = user.insert(&db).await?;
println!("Created user with id={}", created.id);

How the ORM Works

The Kungfu.js ORM uses parameterized queries. This means user input never gets interpolated into SQL strings. Instead, placeholders like $1, $2 are used, and the actual values are passed separately. This makes SQL injection impossible.

For example, if you search for a user by email, the ORM generates: SELECT * FROM users WHERE email = $1 and passes the email value as a parameter. Even if the email contains SQL code like ' OR 1=1 --, it is treated as a plain string, not as SQL.

Common Mistakes

• Not reading the documentation: Always check the API reference when something does not work as expected.
• Skipping security: Never disable the default middleware unless you have a very good reason. Security is not optional.
• Not testing: Write tests for your handlers. Kungfu.js makes this easy with the built-in test utilities.

Summary

In this chapter, you learned about crud: create in JavaScript. You saw code examples, understood how things work under the hood, and learned about common mistakes to avoid.

What is Next?

In chapter 24, we will cover CRUD: Read: Query rows with WHERE, ORDER, LIMIT.