Composite idAttributes

[tgriesser]

Beginning a branch to address #86 - composite idAttribute keys on models.

So far, I've only got a rough implementation of the base model. I still need to figure out how this will play into the relations, but I figured if anyone has ideas or opinions they could chime in here.

/cc @brianjmiller - I think you were the one mentioning looking for this feature, do you have any thoughts on what the api should look like when forming relations on models that have multiple column pk's?

[brianjmiller]

I don't really have any great ideas. The one other ORM I've used to any great extent supported it and it is one of the few that I know of that does, so might be able to have a look at how they implemented them. From the Perl world, but overall same goal:

https://metacpan.org/pod/Rose::DB::Object

[linaGirl]

hi, whats the progress on this issue? it would be really nice to have this feature.

[tgriesser]

Hey @eventEmitter - so I got the basics down for creating models with compound id's... but I'm not certain about how relation loading/pairing should work here.

Eager loading depend on where in queries, which I don't believe will work with multiple keys without a bit of an overhaul on how the queries are composed.

How do you anticipate using this feature (what types of relations, etc) - that might help me visualize how to best build this out.

[huliseerow]

Hey @tgriesser I'm answering on behalf of @eventEmitter. We use it mostly for internationalization. Meaning we have a table for example Country for this table we hava a CountryLocale Table with the country_id, language_id and the name of the Country in the corresponding language. So the PrimaryKey of CountryLocale is composed of the two keys id_language and id_country.

[nathasm]

Is this a dead issue? Or are there still plans for composite key support?

[TheBeege]

Hey @tgriesser - I'm dead in the water without this. I'll throw a use case at you in the event it helps.

We have timelines, posts, events, and users. A user can place an event on a timeline by creating a post. Timelines and events belong to many of each other through posts. Posts also belong to a user. Our post table looks like this:

CREATE TABLE posts
(
  timeline_id integer NOT NULL,
  event_id integer NOT NULL,
  create_date timestamp without time zone,
  poster integer,
  CONSTRAINT posts_pkey PRIMARY KEY (timeline_id, event_id)
)

Weird, part is, I found mention of composite keys at http://minocys.azurewebsites.net/designing-postgresql-tables-with-composite-keys/. When using this in practice, I hit Unhandled rejection error: column "id" does not exist. The debug output looks like this:

{
    method: 'insert',
    options: {},
    bindings: ['2015-09-01 00:00:00', 31, 474, 146],
    sql: 'insert into "posts" ("create_date", "event_id", "poster", "timeline_id") values (?, ?, ?, ?) returning "id"',
    returning: 'id'
}

It's trying to spit out an ID, even though I've specified idAttributes on my Post model as ['timeline_id', 'event_id'].

Is this evidence of BookshelfJS still not supporting composite keys, or is this some sort of unrelated bug?

EDIT: If you need help with this at all, I'm heavily invested in BookshelfJS due to this project. If I can get some context, I'll do the best I can.

[rhys-vdw]

Is this evidence of BookshelfJS still not supporting composite keys, or is this some sort of unrelated bug?

Composite keys are unsupported. Adding comprehensive support would be difficult (eg. certain relation types). It would be easier to add partial support (eg. allowing the operation you're going for there by not trying to return id). If you'd like to open a new issue per supported feature we can discuss on a case by case basis and try to get some better behaviour for you.

However what you're describing is (in Bookshelf terms) a many to many relationship with a pivot table (in this case you can describe this without creating a specific model for posts.

var Event, Timeline;

var postColumns = ['create_date', 'poster'];

Event = bookshelf.Model.extend({
  tableName: 'events',
  events() {
    return this.belongsToMany(Timeline, 'posts').withPivot(postColumns);
  }
});

Timeline = bookshelf.Model.extend({
  tableName: 'timelines',
  events() {
    return this.belongsToMany(Event, 'posts').withPivot(postColumns);
  }
});

Timeline.forge({ id: 5 }).related('events').create({ /* event fields */ });

[rluba]

@rhys-vdw But how would you set create_date and poster in this example when using .create(…)?

Related: How would you insert a new Event-Timeline relation for an existing Event and existing Timeline and set create_date and poster as part of the INSERT? Using attach and then updatePivot requires two roundtrips to the database and is impossible if eg. poster is a required field.

[rluba]

Answered my own question in #648.

[jcowgar]

Another ORM I have explored recently does composite relation keys as an array. Translating to Bookshelf(ish) talk:

return this.belongsTo(Client, ['timeline_id', 'event_id']);

[dnascimento]

Any update on this?

[linaGirl]

For me it's https://www.npmjs.com/package/related

[castarco]

Maybe this PR should be closed.... its too old to be fixed to match the current code base.

[mrhwick]

Closing until re-implementation. Collected all related issues under #1664