Why does my query for stored points throw error[E0277] (the trait bound is not satisfied)?

Question

I'm trying retrieve all points of interest stored in my DB, with the following DB schema:

CREATE TABLE elements (
    id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
    collection_id uuid NOT NULL,
    name TEXT NOT NULL,
    description TEXT,

    CONSTRAINT fk_elements_collections FOREIGN KEY(collection_id) REFERENCES collections(id) ON DELETE CASCADE
);

CREATE TABLE points (
    element_id uuid PRIMARY KEY NOT NULL,
    point geometry(Point,4326) NOT NULL,

    CONSTRAINT fk_points_elements FOREIGN KEY(element_id) REFERENCES elements(id) ON DELETE CASCADE
);

That it's translated to diesel schema as:


diesel::table! {
    use diesel::sql_types::*;
    use diesel::pg::sql_types::*;
    use postgis_diesel::sql_types::*;

    elements (id) {
        id -> Uuid,
        collection_id -> Uuid,
        name -> Text,
        description -> Nullable<Text>,
    }
}

diesel::table! {
    use diesel::sql_types::*;
    use diesel::pg::sql_types::*;
    use postgis_diesel::sql_types::*;
    use super::sql_types::Geometry;

    points (element_id) {
        element_id -> Uuid,
        point -> Geometry,
    }
}

I'm trying to query all the points that are part of a collection with this code:

use diesel::Queryable;
use postgis_diesel::types::Point;
use serde::{Deserialize, Serialize};

#[derive(Debug, Serialize, Deserialize, Queryable)]
pub struct PointOfInterest {
    pub id: uuid::Uuid,
    pub collection_id: uuid::Uuid,
    pub name: String,
    pub description: Option<String>,
    pub point: Point,
}


elements::table
    .inner_join(points::table)
    .filter(elements::collection_id.eq(collection))
    .select((
        elements::id,
        elements::collection_id,
        elements::name,
        elements::description,
        points::point,
    ))
    .load::<PointOfInterest>(connection)

But I'm getting this error:

error[E0277]: the trait bound `(diesel::sql_types::Uuid, diesel::sql_types::Uuid, diesel::sql_types::Text, diesel::sql_types::Nullable<diesel::sql_types::Text>, schema::sql_types::Geometry): load_dsl::private::CompatibleType<PointOfInterest, Pg>` is not satisfied
    --> src/domain/points/repo.rs:43:46
     |
43   |                     .load::<PointOfInterest>(connection)
     |                      ----                    ^^^^^^^^^^ the trait `load_dsl::private::CompatibleType<PointOfInterest, Pg>` is not implemented for `(diesel::sql_types::Uuid, diesel::sql_types::Uuid, diesel::sql_types::Text, diesel::sql_types::Nullable<diesel::sql_types::Text>, schema::sql_types::Geometry)`
     |                      |
     |                      required by a bound introduced by this call
     |

For what I've tested, if I remove the point field of my PointOfInterest struct and from the select statement, I do get things to work.

After almost a week of investigation, and after reading among some others, this two answers about this issue:

I came to the conclusion that the Point type that I'm using from the diesel_postgis library must be missing a trait, but I'm unable to make any progress on this regard. Could somebody give me a hand in trying to figure out how to get from here?

Relevant versions:

diesel = { version = "2.1.0", features = ["postgres", "uuid"] }
postgis_diesel = { version = "2.1.0", features = ["serde"] }
uuid = { version = "1.2.1", features = ["serde", "v7"] }
serde = { version = "1.0.136", features = ["derive"] }

Why does my query for stored points throw error[E0277] (the trait bound is not satisfied)?

0 Answers0