Defining Models

A model is a Rust struct annotated with #[derive(toasty::Model)]. Each struct maps to a database table and each field maps to a column.

#![allow(unused)]
fn main() {
#[derive(Debug, toasty::Model)]
struct User {
    #[key]
    #[auto]
    id: u64,

    name: String,
    email: String,
}
}

This defines a User model that maps to a users table with three columns. In SQLite, the generated table looks like:

CREATE TABLE users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    email TEXT NOT NULL
);

Each struct field becomes a column. Required fields (String, u64, etc.) map to NOT NULL columns. The #[key] attribute marks the primary key, and #[auto] tells Toasty to auto-generate the value on insert.

Supported field types

Toasty supports these Rust types as model fields:

With optional feature flags:

Enable feature flags in your Cargo.toml:

[dependencies]
toasty = { version = "0.1", features = ["sqlite", "jiff"] }

Optional fields

Wrap a field in Option<T> to make it nullable. An Option<T> field maps to a nullable column in the database — the column allows NULL values instead of requiring NOT NULL.

#![allow(unused)]
fn main() {
#[derive(Debug, toasty::Model)]
struct User {
    #[key]
    #[auto]
    id: u64,

    name: String,
    bio: Option<String>,
}
}

The bio field produces a nullable column:

CREATE TABLE users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    bio TEXT          -- nullable, allows NULL
);

When creating a record, optional fields default to NULL if not set:

#![allow(unused)]
fn main() {
use toasty::Model;
#[derive(Debug, toasty::Model)]
struct User {
    #[key]
    #[auto]
    id: u64,
    name: String,
    bio: Option<String>,
}
async fn __example(mut db: toasty::Db) -> toasty::Result<()> {
// bio will be NULL in the database, None in Rust
let user = User::create()
    .name("Alice")
    .exec(&mut db)
    .await?;
Ok(())
}
}

Table names

Toasty auto-pluralizes the struct name to derive the table name. User becomes users, Post becomes posts.

Override the table name with #[table]:

#![allow(unused)]
fn main() {
#[derive(Debug, toasty::Model)]
#[table = "people"]
struct User {
    #[key]
    #[auto]
    id: u64,

    name: String,
}
}

This maps to a table named people instead of the default users.

What gets generated

For a model with basic fields (no relationships or indexes), #[derive(Model)] generates:

Static methods on the model:

#![allow(unused)]
fn main() {
use toasty::Model;
#[derive(Debug, toasty::Model)]
struct User {
    #[key]
    #[auto]
    id: u64,
    name: String,
}
fn __example() {
// Returns a create builder
let _ =
User::create();

// Returns a builder for bulk inserts
let _ =
User::create_many();

// Returns a query builder for all records
let _ =
User::all();

// Returns a query builder with a filter applied
let _ =
User::filter(User::fields().name().eq("Alice"));

// Returns field accessors (for building filter expressions)
let _ =
User::fields();
}
}

Instance methods:

#![allow(unused)]
fn main() {
use toasty::Model;
#[derive(Debug, toasty::Model)]
struct User {
    #[key]
    #[auto]
    id: u64,
    name: String,
}
fn __example(mut user: User) {
// Returns an update builder for this record
let _ =
user.update();

// Returns a delete builder for this record
let _ =
user.delete();
}
}

Builders:

• The create builder returned by User::create() has a setter method for each non-auto field. Chain setters and call .exec(&mut db) to insert:

  #![allow(unused)]
  fn main() {
  use toasty::Model;
  #[derive(Debug, toasty::Model)]
  struct User {
      #[key]
      #[auto]
      id: u64,
      name: String,
      email: String,
  }
  async fn __example(mut db: toasty::Db) -> toasty::Result<()> {
  let user = User::create()
      .name("Alice")
      .email("alice@example.com")
      .exec(&mut db)
      .await?;
  Ok(())
  }
  }

• The update builder returned by user.update() has a setter for each field. Only set the fields you want to change:

  #![allow(unused)]
  fn main() {
  use toasty::Model;
  #[derive(Debug, toasty::Model)]
  struct User {
      #[key]
      #[auto]
      id: u64,
      name: String,
      email: String,
  }
  async fn __example(mut user: User, mut db: toasty::Db) -> toasty::Result<()> {
  user.update()
      .name("Bob")
      .exec(&mut db)
      .await?;
  Ok(())
  }
  }

• The query builder returned by User::all() or User::filter() has methods like .exec(), .first(), .get(), and .collect::<Vec<_>>() to execute the query.

What types can you pass to setters?

Builder setters accept more than just the exact field type. For a String field, you can pass a String, a &str, or even an Option<String>. For numeric fields, you can pass the value directly or a reference. This works through Toasty’s IntoExpr trait, which handles the conversion automatically.

#![allow(unused)]
fn main() {
use toasty::Model;
#[derive(Debug, toasty::Model)]
struct User {
    #[key]
    #[auto]
    id: u64,
    name: String,
}
fn __example() {
// String literal (&str)
let _ =
User::create().name("Alice");

// Owned String
let name = "Bob".to_string();
let _ =
User::create().name(name);

// Reference to a String
let name = "Carol".to_string();
let _ =
User::create().name(&name);
}
}

You don’t need to call .to_string() or .clone() to satisfy the setter — pass the value in whatever form you have it.

Additional methods are generated when you add attributes like #[key], #[unique], and #[index]. The next chapters cover these.