findOrCreate without id

[SamuelTilly]

I am unable to make findOrCreate work without knowing the model id on beforehand.

Entity.findOrCreate({slug: params.urlSlug}, {create: false})

Then i would need to create a new model but as soon as i make a fetch and it retrieve it's data it will give me the "Cannot instantiate more than one Backbone.RelationalModel" error.

if i specify id it works tho:

Entity.findOrCreate({id: 1, slug: params.urlSlug}, {create: false})

[wolverdude]

I'm having the same issue. It's a bit of a catch-22 because I can't get the model without the id, but I can't fetch the id because I don't have the model. Fortunately, I figured out this method (not in the docs):

Backbone.Relational.store.getCollection(<Backbone.Model>).findWhere(<attributes>)

If I hadn't found that, I would've been stuck. It would be nice if there were a simpler way to do this.

[itayadler]

what parameter u pass to getCollection?

[wolverdude]

Sorry, I didn't have it marked as code, so markdown thought my parameters were actually tags. Documentation for Collection#findWhere() is on the Backbone Docs page.

[PaulUithol]

I've just added a method (RelationalModel.findModel) that might help for this case as well, see 8371089. It allows you to customize the matching for creation or updates, using whichever attributes of a model you choose.