How to Access a Junction Table via Entity Loader?

[thetwistedlogic]

Say, I have a database designed like so:

• media has a many to many relationship with the tag table
• media_tag, the junction table, has extra metadata specific to the relation within it (such as whether the tag is a spoiler)

Here is how I've designed the tables:

// tag.rs
use sea_orm::entity::prelude::*;
use serde::{Deserialize, Serialize};

#[sea_orm::model]
#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel, Serialize, Deserialize)]
#[sea_orm(table_name = "tag")]
pub struct Model {
    #[sea_orm(primary_key)]
    pub id: i64,
    #[sea_orm(unique)]
    pub name: String,
    #[sea_orm(has_many, via = "media_tag")]
    pub media: HasMany<super::media::Entity>,
}

impl ActiveModelBehavior for ActiveModel {}

// media.rs
use sea_orm::entity::prelude::*;
use serde::{Deserialize, Serialize};

#[sea_orm::model]
#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel, Serialize, Deserialize)]
#[sea_orm(table_name = "media")]
pub struct Model {
    #[sea_orm(primary_key)]
    pub id: i64,
    // excluded many fields for brevity
    #[sea_orm(has_many, via = "media_tag")]
    pub tag: HasMany<super::tag::Entity>,
}

impl ActiveModelBehavior for ActiveModel {}

// media_tag.rs
use sea_orm::entity::prelude::*;
use serde::{Deserialize, Serialize};

#[sea_orm::model]
#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel, Serialize, Deserialize)]
#[sea_orm(table_name = "media_tag")]
pub struct Model {
    // Many to Many stuff
    #[sea_orm(primary_key, auto_increment = false)]
    pub media_id: i64,
    #[sea_orm(primary_key, auto_increment = false)]
    pub tag_id: i64,
    #[sea_orm(belongs_to, from = "media_id", to = "id")]
    pub media: Option<super::media::Entity>,
    #[sea_orm(belongs_to, from = "tag_id", to = "id")]
    pub tag: Option<super::tag::Entity>,
    #[sea_orm(default_value = false)]
    pub spoiler: bool,
}

impl ActiveModelBehavior for ActiveModel {}

Here is how I query the data using Entity Loader:

entity::media::Entity::load()
        .with(entity::tag::Entity)
        .all(db)
        .await

This returns a vector of entity::media::ModelEx, which has each media object as well as their associate tags as an array. This is excellent but it misses the metadata from the junction table! Is there something I'm missing, perhaps an alternative method that isn't .with()?

[Huliiiiii]

find_also_related?

[thetwistedlogic]

This is functional (and is likely what I will use moving forward). However, it's not the Entity Loader pattern like my question suggested.

[Huliiiiii]

You can model it as related entities, for example:

#[sea_orm(has_many)]
pub media_tags: HasMany<super::media_tag::Entity>,

Then:

let media = entity::media::Entity::load()
    .with((entity::media_tag::Entity, entity::tag::Entity))
    .all(db)
    .await?;