Skip to main content
Version: 1.2.x 🚧

Select

Once you have defined the entity, you are ready to retrieve data from the database. Each row of data in the database corresponds to a Model.

By default, SeaORM will select all columns defined in the Column enum.

Find by Primary Key​

Find a model by its primary key, it can be a single key or composite key. We start by calling find_by_id on Entity which helps you construct the select query and condition automatically. Then, fetch a single model from the database with the one method.

use super::cake::Entity as Cake;
use super::cake_filling::Entity as CakeFilling;

// Find by primary key
let cheese: Option<cake::Model> = Cake::find_by_id(1).one(db).await?;

// Find by composite primary keys
let vanilla: Option<cake_filling::Model> = CakeFilling::find_by_id((6, 8)).one(db).await?;

Find with Conditions and Orders​

In addition to retrieving a model by primary key, you can also retrieve one or more models matching specific conditions in a certain order. The find method gives you access to the query builder in SeaORM. It supports the construction of all common select expressions like where and order by. They can be constructed using filter and order_by_* methods respectively.

Read more about conditional expression.

let chocolate: Vec<cake::Model> = Cake::find()
    .filter(cake::Column::Name.contains("chocolate"))
    .order_by_asc(cake::Column::Name)
    .all(db)
    .await?;

Read more on the Relation chapter.

Lazy Loading​

Use the find_related method.

Related models are loaded on demand when you ask for them, preferable if you want to load related models based on some application logic. Note that lazy loading will increase database round trips compared to eager loading.

// Find a cake model first
let cheese: Option<cake::Model> = Cake::find_by_id(1).one(db).await?;
let cheese: cake::Model = cheese.unwrap();

// Then, find all related fruits of this cake
let fruits: Vec<fruit::Model> = cheese.find_related(Fruit).all(db).await?;

Eager Loading​

All related models are loaded at once. This provides minimum database round trips compared to lazy loading.

One to One​

Use the find_also_related method.

let fruits_and_cakes: Vec<(fruit::Model, Option<cake::Model>)> = Fruit::find().find_also_related(Cake).all(db).await?;

One to Many / Many to Many​

Using the find_with_related method, the related models will be grouped by the parent models. This method handles both 1-N and M-N cases, and will perform 2 joins when there is a junction table involved.

let cake_with_fruits: Vec<(cake::Model, Vec<fruit::Model>)> = Cake::find()
    .find_with_related(Fruit)
    .all(db)
    .await?;

Batch Loading​

Since 0.11, we introduced a LoaderTrait to load related entities in batches.

Compared to eager loading, it saves bandwidth (consider the one to many case, the one side rows may duplicate) at the cost of one (or two, in the case of many to many) more database roundtrip.

One to One​

Use the load_one method.

let fruits: Vec<fruit::Model> = Fruit::find().all(db).await?;
let cakes: Vec<Option<cake::Model>> = fruits.load_one(Cake, db).await?;

One to Many​

Use the load_many method.

let cakes: Vec<cake::Model> = Cake::find().all(db).await?;
let fruits: Vec<Vec<fruit::Model>> = cakes.load_many(Fruit, db).await?;

Many to Many​

Use the load_many_to_many method. You have to provide the junction Entity.

let cakes: Vec<cake::Model> = Cake::find().all(db).await?;
let fillings: Vec<Vec<filling::Model>> = cakes.load_many_to_many(Filling, CakeFilling, db).await?;

Paginate Result​

Convert any SeaORM select into a paginator with custom page size.

use sea_orm::{entity::*, query::*, tests_cfg::cake};
let mut cake_pages = cake::Entity::find()
    .order_by_asc(cake::Column::Id)
    .paginate(db, 50);
 
while let Some(cakes) = cake_pages.fetch_and_next().await? {
    // Do something on cakes: Vec<cake::Model>
}

Cursor Pagination​

Use cursor pagination If you want to paginate rows based on column(s) such as the primary key.

use sea_orm::{entity::*, query::*, tests_cfg::cake};
// Create a cursor that order by `cake`.`id`
let mut cursor = cake::Entity::find().cursor_by(cake::Column::Id);

// Filter paginated result by `cake`.`id` > 1 AND `cake`.`id` < 100
cursor.after(1).before(100);

// Get first 10 rows (order by `cake`.`id` ASC)
for cake in cursor.first(10).all(db).await? {
    // Do something on cake: cake::Model
}

// Get last 10 rows (order by `cake`.`id` DESC but rows are returned in ascending order)
for cake in cursor.last(10).all(db).await? {
    // Do something on cake: cake::Model
}

Paginate rows based on a composite primary key is also available.

use sea_orm::{entity::*, query::*, tests_cfg::cake_filling};
let rows = cake_filling::Entity::find()
    .cursor_by((cake_filling::Column::CakeId, cake_filling::Column::FillingId))
    .after((0, 1))
    .before((10, 11))
    .first(3)
    .all(&db)
    .await?,

Select custom​

If you want to select custom columns and expressions, read the custom select section.