A safe, extensible ORM and Query Builder for Rust

API Documentation: latest release – master branch

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Diesel gets rid of the boilerplate for database interaction and eliminates runtime errors without sacrificing performance. It takes full advantage of Rust's type system to create a low overhead query builder that "feels like Rust."

Supported databases:

1. PostgreSQL
2. MySQL
3. SQLite

You can configure the database backend in Cargo.toml:

[dependencies]
diesel = { version = "", features = [""] }

Getting Started

Find our extensive Getting Started tutorial at https://diesel.rs/guides/getting-started. Guides on more specific features are coming soon.

Getting help

If you run into problems, you can come ask for help at in our GitHub Discussions forum. This is also the right place to propose new features or show your applications.

Usage

Simple queries

Simple queries are a complete breeze. Loading all users from a database:

users::table.load(&mut connection)

Executed SQL:

SELECT * FROM users;

Loading all the posts for a user:

Post::belonging_to(user).load(&mut connection)

Executed SQL:

SELECT * FROM posts WHERE user_id = 1;

Complex queries

Diesel's powerful query builder helps you construct queries as simple or complex as you need, at zero cost.

let versions = Version::belonging_to(krate)
  .select(id)
  .order(num.desc())
  .limit(5);
let downloads = version_downloads
  .filter(date.gt(now - 90.days()))
  .filter(version_id.eq_any(versions))
  .order(date)
  .load::(&mut conn)?;

Executed SQL:

SELECT version_downloads.* FROM version_downloads
  WHERE date > (NOW() - '90 days')
    AND version_id = ANY(
      SELECT id FROM versions
        WHERE crate_id = 1
        ORDER BY num DESC
        LIMIT 5
    )
  ORDER BY date

Less boilerplate

Diesel codegen generates boilerplate for you. It lets you focus on your business logic, not mapping to and from SQL rows.

That means you can write this:

#[derive(Queryable, Selectable)]
#[diesel(table_name = downloads)]
pub struct Download {
    id: i32,
    version_id: i32,
    downloads: i32,
    counted: i32,
    date: SystemTime,
}

Instead of this without Diesel:

pub struct Download {
    id: i32,
    version_id: i32,
    downloads: i32,
    counted: i32,
    date: SystemTime,
}

impl Download {
    fn from_row(row: &Row) -> Download {
        Download {
            id: row.get("id"),
            version_id: row.get("version_id"),
            downloads: row.get("downloads"),
            counted: row.get("counted"),
            date: row.get("date"),
        }
    }
}

Inserting data

It's not just about reading data. Diesel makes it easy to use structs for new records.

#[derive(Insertable)]
#[diesel(table_name = users)]
struct NewUser