MongoDB对象类型/嵌套模式

Question

Okay so I have an events.js file with an eventSchema:

var eventSchema = mongoose.Schema({
name:{
    type: String,
    //required: true
venue:{

}
});

and a venue.js with the venue schema:

var mongoose = require('mongoose');

var venueSchema = mongoose.Schema(
{
name:{
    type: String,
    //required: true
},
postcode:{
    type: String,
    //required: true
},
town:{
    type: String,
    //required: true
}
});

My question is how can I have the 'venue' field in the events schema be linked to the venue schema. So essentially when you create a new event you can only add a venue from the list of venues. Thanks in advance!

Answer 1

You can link it by id. You don't have to add all 'venue' field in the events schema.

var eventSchema = mongoose.Schema({
  name:{
    type: String,
    //required: true
  },
  venue_id: Schema.Types.ObjectId,
});

Since you're using Mongoose, You can make field like,

venue_id: { type: Schema.Types.ObjectId, ref: 'Venue' }

which uses populate method.

Population is the process of automatically replacing the specified paths (which is venue_id) in the document with document(s) from other collection(s) (which is document matched with venue_id).

You can use it like

event.
  findOne({ name: 'somename' }).
  populate('venue').
  exec(function (err, event) {
    if (err) return handleError(err);
});

It will return event doc with venue doc that match with venue_id, not just venue_id.

Answer 2

The answer given by @godsnam is correct but when you want to use references in your schema. If you don't want to do it using references then this might help you.

You can do link your venueSchema in eventSchema by simply writing as below.

var venueSchema = mongoose.Schema(
    {
        name: {
            type: String,
            //required: true
        },
        postcode: {
            type: String,
            //required: true
        },
        town: {
            type: String,
            //required: true
        }
    });

var eventSchema = mongoose.Schema({
    name: {
        type: String,
        //required: true
    },
    venue: venueSchema
});