Rust crate review: Diesel vs SQLx

Rust is quickly gaining popularity and becoming a go-to language for many developers. But, as with any language, it's only as good as the libraries and tools that accompany it. In this article, we're going to dive into two popular Rust crates: Diesel and SQLx.

Both Diesel and SQLx are libraries that aim to simplify database interactions in Rust. But which one is better? Let's find out!

Diesel

Diesel describes itself as a "safe, extensible ORM and Query Builder for Rust." It supports multiple database backends, including PostgreSQL, MySQL, and SQLite. Diesel's API is designed to be familiar to those who have used SQL before, making it easy to get started with.

One of the great things about Diesel is its safety features. Diesel uses Rust's type system to ensure that your database interactions are safe and secure. For example, if you have a query that returns a string, you can't accidentally try to assign it to an integer.

let name: String = users.select(name).first(&conn)?;
let age: i32 = users.select(age).first(&conn)?;
// This won't compile
// let age: String = users.select(age).first(&conn)?;

Querying with Diesel is also very easy. Here's an example of a simple query:

let users = users.filter(age.gt(18)).load(&conn)?;

This will return all users that are over 18 years old.

Another great feature of Diesel is its query generation. Diesel is able to generate SQL for you based on Rust code. This makes it easier to write complex queries without having to write raw SQL. And since Diesel generates the SQL for you, there's less chance of making a typo or other error.

Overall, Diesel is a great choice if you want a safe and easy-to-use ORM for Rust. But let's take a look at SQLx and see how it compares.

SQLx

SQLx is a more recent addition to the Rust database world, but it's quickly gaining popularity. SQLx is different from Diesel in that it's not an ORM. Instead, SQLx is a "modern SQL query engine for Rust." SQLx aims to make it as easy as possible to work with databases in Rust.

One of the biggest benefits of SQLx is its flexibility. SQLx can work with any database that supports the SQL language. This includes PostgreSQL, MySQL, SQLite, and more. This means that you can use the same Rust code to communicate with different databases.

SQLx also offers a simpler API than Diesel. Here's an example of a query with SQLx:

let user = sqlx::query("SELECT * FROM users WHERE id = $1")
    .bind(user_id)
    .fetch_one(&mut conn)
    .await?;

This will fetch a single user with the given user_id. The syntax is similar to raw SQL, which makes it easy for those familiar with SQL to get started with.

Another great feature of SQLx is its support for async/await. Since database IO can be slow, it's important to be able to run database queries asynchronously. SQLx is designed to work with Rust's async/await functionality, making it easy to write async code that queries a database.

Conclusion

So, which one is better: Diesel or SQLx? It's difficult to say. Both libraries have their strengths and weaknesses, and the right choice depends on your specific use case.

If you're looking for an ORM that's safe and easy to use, Diesel is a great choice. Its type system guarantees safe database interactions, and its query generation feature makes it easy to write complex queries.

On the other hand, if you're looking for a more flexible SQL query engine that can work with any database and supports async/await, SQLx is a great choice. Its API is simple and easy to use, and its async support makes it a good option for high-performance applications.

Ultimately, both Diesel and SQLx are excellent choices for database interactions in Rust. Whichever one you choose, you can be confident that you're getting a high-quality library that will make working with databases in Rust a breeze.

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