Query nested relations recursively

[agnes512]

Suggestion

Original from comment.

LoopBack 4 provides the custom scope to achieve inclusion, which was implemented in #3454. But it only goes down to the certain levels of relations that are described in the filter, for example, three levels:

    const filter = {
      include: [
        {
          relation: 'nested 1',
          scope: {
            include: [{relation: 'nested 2'}],
          },
        },
      ],
    };

It'd be good to have a better way to query nested relations to max depth/ N degrees, something like {relation: "nested", depth: 10}.

Examples

Model Comment has many replies: Comment[], and comments in the replies has many replies, etc. Returns when there is no more replies or the max depth is reached.

Acceptance criteria

• [ ] Provide a way to query nested relations to max depth/ N degrees, or at least to have a helper function for writing the filter.
• [ ] Should document how to configure the max depth of such traverses.

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[talhakca]

Is there any update about this issue ?

[achrinza]

No updates at the moment.

[mauricioA0]

hey All,

we are doing a research using TypeORM and loopback 4 but there are a couple of issues on models. Eg how to setup relations manyToOne.

Do you have any ideo how to hooks repositories to avoid to use N+1 query? there are too many connection to the database. lb3 https://loopback.io/doc/en/lb3/Nested-queries.html

Maybe use include as another ORM could help to avoid and scale more application.

A quick solution for us is use custom query but I am not sure if that could be the best solution. Also, we are going to use elastic search in our API.

My second approach is create a handler in all my request and make queries then map that result in the repositories.