If I have a model Attachment, which can be divided into 4 types: Link, YoutubeVideo, GoogleDriveFile, and GoogleDriveFolder, how can I use Mongoose to discriminate Attachment into these types, and allow them to be subdocuments in another schema; Post?
I've created the base Attachment model, and divided it into separate models using discriminators:
var AttachmentSchema = new Schema({
id: {type: String, required: true},
title: {type: String, required: true}
});
var Attachment = mongoose.model('Material', AttachmentSchema);
module.exports = {
DriveFile: Attachment.discriminator('GoogleDriveFile', new mongoose.Schema()),
DriveFolder: Attachment.discriminator('GoogleDriveFolder', new mongoose.Schema()),
Link: Attachment.discriminator('Link', new mongoose.Schema()),
YoutubeVideo: Attachment.discriminator('YoutubeVideo', new mongoose.Schema())
};
Now, in the Post schema, there should be an array of attachments, with varying types:
var Attachment = require('./attachment');
var PostSchema = new Schema(
text:{type: String},
attachments: [Material] // Could be Material.Link, Material.YoutubeVideo, etc
});
When I do this, I get an error saying "Undefined type Model at GoogleDriveFile. Did you try nesting Schemas? You can only nest using refs or arrays."
I don't know what this error means, and I can't find any docs explaining how to do this. Help?
Try doing the following:
var AttachmentSchema = new Schema({
id: {type: String, required: true},
title: {type: String, required: true}
});
var PostSchema = new Schema({
text: { type: String },
attachments: [ AttachmentSchema ] // Could be Material.Link, Material.YoutubeVideo, etc
});
var attachmentArray = PostSchema.path('attachments');
module.exports = {
Post: mongoose.model('Post', PostSchema),
DriveFile: attachmentArray.discriminator('GoogleDriveFile', new mongoose.Schema({})),
DriveFolder: attachmentArray.discriminator('GoogleDriveFolder', new mongoose.Schema({})),
Link: attachmentArray.discriminator('Link', new mongoose.Schema({})),
YoutubeVideo: attachmentArray.discriminator('YoutubeVideo', new mongoose.Schema({}))
};
The key is to NOT use a mongoose Model use the schema.path of the parent document schema as the base for your discriminators.
search for the term docArray on this link: Mongoose Discriminator documentation
Related
I am new to mongoose and I was strugling whole day trying to understand populate. I managed to do simple examples but now I created two schemas:
First which is UserSchema with some user details:
const UserSchema: mongoose.Schema = new mongoose.Schema ({
name: String,
email: String
});
And second which is MatchSchema witch I want to be populated with user details but I am not sure if something like this will work:
const MatchSchema: mongoose.Schema = new mongoose.Schema ({
player_one: {
id: String,
score: Number,
player_details: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}
},
player_two: {
id: String,
score: Number,
player_details: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}
},
winner: String
},{timestamps: true});
Probably I used something which wont work and any help will be appriciated.
You need to create a Mongoose model using the UserSchema and name it 'User'. You can then create a Match model using the MatchSchema. Assuming the UserSchema and MatchSchema are in the same file, you can add the following:
const User = mongoose.model('User', UserSchema)
const Match = mongoose.model('Match', MatchSchema)
Then when you want to populate the Match model with User data:
let data = Match.find({})
.populate('player_one.player_details')
.populate('player_two.player_details')
Silly question here, but I'm having trouble finding an example on the web.
I have set up a model on mongoDB that has arrays of objects, like so:
var ProjectSchema = new Schema({
project_id: { type: String },
item: {
title: { type: String },
owners: [{
first_name : {type: String} ,
middle_name : {type: String},
other_name: {type: String},
last_name: {type: String},
order: {type: Number, 'default': 1}
}]
}
}]
So you can see that item is a list of fields. And then owners is an array of lists of fields. When I create the project, I'm trying to set the owner like this:
var newProject = new Models.Project({
'item.title': title,
'item.owners[0].last_name': name,
'item.owners[0].order': 1
});
This doesn't generate an error, but the item fields don't get saved either (item.title saves fine).
I tried this too, but it gives me an error:
var newProject = new Models.Project({
'item.title': title,
item.owners.push({last_name: name, order: 1})
});
How am I supposed to refer to these sub-docs so I can save them?
Don't use dot notation in the fields of a new document, create it using the actual structure of the doc instead:
var newProject = new Models.Project({
item: {
title: title,
owners: [{
last_name: name,
order: 1
}]
});
it is a simple JSON object. With Javascript, it is quite straight forward. Below code generates the sample object given in the mongoDB doc:
var address1 = new Object();
address1.street = "123 Fake Street";
address1.city = "Faketon";
address1.state = "MA";
address1.zip = "12345";
var address2 = new Object();
address2.street = "1 Some other Street";
address2.city = "Boston";
address2.state = "MA";
address2.zip = "12345";
var data = new Object();
data._id = "joe";
data.name = "Joe Bookreader";
var addressArray = new Array();
addressArray.push(address1);
addressArray.push(address2);
data.addresses = addressArray;
alert(JSON.stringify(data));
I'm defining my schema in mongoose and I have an array of book objects, and then an "active book". Now setting it up wasn't an issue, but this seems like unnecessary repetition to define the exact same book object in two different parts of the schema.
var BookSchema = new Schema({
activeBook: {
id: String,
title: String,
author: String,
pages: Number
},
books: [{
id: String,
title: String,
author: String,
pages: Number
}]
});
Is there a cleaner way of writing this so I don't have to write out the same object everywhere I use it?
A cleaner way would be to create a subdocument, a document with a schema of its own which are elements of a parent's document array. So in your example above you can define the child/parent schema as follows:
var ChildSchema = new Schema({
id: String,
title: String,
author: String,
pages: Number
});
var ParentSchema = new Schema({
activeBook: ChildSchema,
books: [ChildSchema]
});
so I've been at it for like 4 hours, read the documentation several times, and still couldn't figure out my problem. I'm trying to do a simple populate() to my model.
I have a User model and Store model. The User has a favoriteStores array which contains the _id of stores. What I'm looking for is that this array will be populated with the Store details.
user.model
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var UserSchema = new Schema({
username: String,
name: {first: String, last: String},
favoriteStores: [{type: Schema.Types.ObjectId, ref: 'Store'}],
modifiedOn: {type: Date, default: Date.now},
createdOn: Date,
lastLogin: Date
});
UserSchema.statics.getFavoriteStores = function (userId, callback) {
this
.findById(userId)
.populate('favoriteStores')
.exec(function (err, stores) {
callback(err, stores);
});
}
And another file:
store.model
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var StoreSchema = new Schema({
name: String,
route: String,
tagline: String,
logo: String
});
module.exports = mongoose.model('Store', StoreSchema);
After running this what I get is:
{
"_id": "556dc40b44f14c0c252c5604",
"username": "adiv.rulez",
"__v": 0,
"modifiedOn": "2015-06-02T14:56:11.074Z",
"favoriteStores": [],
"name": {
"first": "Adiv",
"last": "Ohayon"
}
}
The favoriteStores is empty, even though when I just do a get of the stores without the populate it does display the _id of the store.
Any help is greatly appreciated! Thanks ;)
UPDATE
After using the deepPopulate plugin it magically fixed it. I guess the problem was with the nesting of the userSchema. Still not sure what the problem was exactly, but at least it's fixed.
I think this issue happens when schemas are defined across multiple files. To solve this, try call populate this way:
.populate({path: 'favoriteStores', model: 'Store'})
How to write multi ref for one property of one mongoose schema, like this(but wrong):
var Schema = mongoose.Schema;
var PeopleSchema = new Schema({
peopleType:{
type: Schema.Types.ObjectId,
ref: ['A', 'B'] /*or 'A, B'*/
}
})
You should add string field to your model and store external model name in it, and refPath property - Mongoose Dynamic References
var Schema = mongoose.Schema;
var PeopleSchema = new Schema({
externalModelType:{
type: String
},
peopleType:{
type: Schema.Types.ObjectId,
refPath: 'externalModelType'
}
})
Now Mongoose will populate peopleType with object from corresponding model.
In the current version of Mongoose i still don't see that multi ref possible with syntax like you want. But you can use part of method "Populating across Databases" described here. We just need to move population logic to explicitly variant of population method:
var PeopleSchema = new Schema({
peopleType:{
//Just ObjectId here, without ref
type: mongoose.Schema.Types.ObjectId, required: true,
},
modelNameOfThePeopleType:{
type: mongoose.Schema.Types.String, required: true
}
})
//And after that
var People = mongoose.model('People', PeopleSchema);
People.findById(_id)
.then(function(person) {
return person.populate({ path: 'peopleType',
model: person.modelNameOfThePeopleType });
})
.then(populatedPerson) {
//Here peopleType populated
}
...