Model with Generics

[oscartbeaumont]

I am working on a crate called async-graphql-relay and have recently redone the public API to make it less cumbersome to use (you can checkout the example folder in the repo). When doing this I introduced a type RelayNodeID which is generic on the Model so it is declared as RelayNodeID<Self>. This is done so that among other things all ID's returned from GraphQL are globally unique and contain information about the specific type they are. This type is a wrapper around a standard Uuidv4 and from a database perspective should be treated this way.

After chatting with @billy1624 he pointed me towards this resource which shows how to implement sea-orm support for custom types. The issue I found with this is that my type is generic and this does not currently seem to be supported by sea-orm. When I run my code the DeriveEntityModel macro panics (refer to the code linked below).

I put together some code here which should help show the sort of syntax I am going for without all the complexity and macros of the async-graphql-relay codebase.

Thanks, @billy1624 for creating PR #400 which is going to be the fix for this.

[tyt2y3]

❄️🎄

[billy1624]

With #400 you could define the following:

#[derive(Clone, Debug, PartialEq, DeriveEntityModel)]
#[sea_orm(table_name = "model")]
pub struct Model {
    #[sea_orm(primary_key)]
    pub id: AccountId<String>,
    pub name: String,
}

But not...

#[derive(Clone, Debug, PartialEq, DeriveEntityModel)]
#[sea_orm(table_name = "model")]
pub struct Model<T> {
    #[sea_orm(primary_key)]
    pub id: AccountId<T>,
    pub name: String,
}

So, I'm think should we also support the use of generics over Model? @tyt2y3

[oscartbeaumont]

PR #400 works perfectly for my usecase. Thanks, @billy1624.
Something to note was that although my original idea was RelayNodeID<Self> this causes a lot of issues because the ID field is copied to some SeaORM internal stuff (Eg. ActiveModel, etc) and those types do not satisfy the expected trait for my code. I fixed this easily by changing it to RelayNodeID<Model>. This could be worth noting in documentation although this is probably something a Rust developer would be able to work out.