How to get a single object from Diesel join

help
1

Hello. Working with rust 1.83, diesel 2.2.5. I have two tables (animal & plan), the first has a foreign key (plan_id) to the second. The tables are modeled with structs. I can do a simple query on the 'animal' table and get back a populated Animal:

fn get_animal(target_id: i32) -> Vec<Animal> {
    use crate::schema::animal::dsl::*;

    let conn = &mut crate::establish_connection();

    let animals = animal
        .find(target_id)
        .select(Animal::as_select())
        .load::<Animal>(conn)
        .expect("Error loading animal!");

    animals
}

However, when I look for examples on how to do a left join between the tables, I only see examples which return two objects. I want to get an 'Animal' back with the 'plan' field of 'Animal' populated with the 'name' field of the corresponding 'Plan', Rather than an 'Animal', and a 'Plan'. If I was writing straight SQL, I could do something like this:

select animal.*, plan.name as plan from animal 
left join "plan" on plan.id = animal.plan_id

Any pointers? Thanks!

2

Does using a VIEW work? For example,

CREATE VIEW complete_animal AS SELECT
    animal.*,
    plan.name AS plan
FROM
    animal
LEFT JOIN
    plan ON plan.id = animal.plan_id;

Then you'll be able to define a table! as normal for the complete animal, and, more importantly, you'll be able to leave the structs that you use to insert into these tables alone.