References

References allow to specify that a field in a model is connected to a concrete document in other collections. For example a Worker model can have a company field that "points to" or references the company where he works in the Company collection.

company :{type: ObjectId, ref: "Company"}

In the database will be only stored the identifier of the referenced element.

{
  "_id": ObjectId("5c7439a947d2102f88ae717a"),
  "name": "Juan",
  "surname": "Lopez",
  "company": ObjectId("5c74393347d2102f88ae7179"),
  "__v": 0
}

By default, RouteInjector will use the main identifier of the referenced model as identifier but in some cases you can reference a document by using other application defined identifier.

Changing the default identifier

In injector.js we can control the identifier that RI uses as a default identifier, typically will be set to _id, the id that Mongo uses by default in all collections.

id: "_id"

It is possible to change it other field, but in this case the type attribute of the reference should match the type of the new identifier, i.e if we choose to use a String identifier:

company :{type: String, ref: "Company"}

And the Company model and injector configuration must be updated accordingly.

injector.js

id: "name"

schema.js

name: {type: String, unique: true, required: true, editOnCreate: true}

Limitations of the references

Route-Injector also supports denormalization that in addition to the identifier, it also stores a copy of some of the fields. This allows faster queries and also some listing capabilities.

More specifically, you can use a reference, keep only the ObjectID, populate the needed fields and list them. But, you cannot sort on this fields because the populated fields are added later. On the other hand, if you use a denormalization, you can sort on this fields because in fact they are present in the database.