Implement `->` operator about diesel_json HOT 3 CLOSED

Hi! Thanks for checking out this library.

For now planned scope is to only provide wrapper type that hides implementation details and provides very simple interface for object serialization to, de-serialization from database json, jsonb values.

For now, to use such query in diesel you can use sql_query. There could be other ways too like extending diesel with adding your own expressions.

For implementing type safe "->" json operator, it would require some kind of similar "dsl" schema definition approach for jsonb structure fields as is done now for database schema in diesel. Of course the schema could be generated by procedural macro from type, but for now it is out of the scope of planned features for this library.

Will give notification if something changes :)

from diesel_json.

Small note, operator "->" is partially supported. The returned data can still be parsed with diesel_json::Json.

If you have query like this: '{"a": {"b":"foo"}}'::jsonb->'a'

And you only need support for retrieving and parsing the returned data. You can do something like this.

    #[derive(Serialize, Deserialize, Debug)]
    struct MyStruct {
        b: String
    }
    #[derive(QueryableByName, Debug)]
    struct SelectLayout {
        #[sql_type = "diesel::sql_types::Jsonb"]
        data: diesel_json::Json<MyStruct>
    }

    let result: Vec<SelectLayout> = sql_query(r#"SELECT '{"a": {"b":"foo"}}'::jsonb->'a' as data"#).load(&connection).unwrap();

from diesel_json.

Actually the snippet above was just an example from the postgres docs. My actual query is more complicated, and I noticed while testing that it also needs the ->> operator. So the raw query you suggested is probably the best option, thanks a lot for that!

from diesel_json.