Simple relationships definitions in Schema

[celrenheit]

It would be nice to handle some simple relationships handling between models.

I propose this configuration:

var UserSchema = new Schema({
    name: String,
    email: String,
    username: String
});


UserSchema.relationships = {
    'createdArticles': {   
        model: 'Article',
        direction: 'OUT',
        edgeLabel: 'created'
    },
    'follows': {
        model: 'User',
        direction: 'OUT',
        edgeLabel: 'follows'
    },
    'followedBy': {
        model: 'User',
        direction: 'IN',
        edgeLabel: 'follows'
    }
};

// AND/OR

UserSchema.relationships.add('createdArticles', {   
    model: 'Article',
    direction: 'OUT',
    edgeLabel: 'created'
})

What do you think ?

[jbmusso]

I've been playing with this in the past. I was thinking about adding 'Reference' property classes to models that could be either 'SingleReference' or 'MultiReference' properties (the latter two would inherit from a ReferenceProperty class). Such properties would be defined in the raw object passed to the Schema constructor.

var PersonSchema = new Schema({
  name: String
  spouse: PersonSchema
  children: [PersonSchema]
});

In this example, spouse would be a SingleReferenceProperty while children would be a MultiReferenceProperty. There would be issues though when naming edge labels, for not all edge labels can be inferred by solely looking at the property name (and users may want customization as well).

A more complex API could be (maybe optionally):

var PersonSchema = new Schema({
  name: String
  spouse: {
    type: PersonSchema,
    cardinality: 'OneToOne'
    label: 'spouseOf'
  }
  children: {
    type: PersonSchema,
    cardinality: 'OneToMany'
    label: 'parentOf'
  }
});

in relationship could be inferred from out relationships, or explicitly set. I don't know :).

The idea is to abstract as much thing as possible if needed, but still allow the user to fine tune and manipulate lower level concepts as well.

Reference properties would then be populated when models are fetched, and maybe only some of them (ie fetch(populate: ['spouse', 'children']), for example).