I'm new to mongoose,
If I want to define a model, I could use the following:
var ArticleSchema = new Schema({
_id: ObjectId,
title: String,
content: String,
time: { type: Date, default: Date.now }
});
var ArticleModel = mongoose.model("Article", ArticleSchema);
But why not just code like this:
var ArticleModel = new Model({
// properties
});
Why was mongoose designed in this way? Is there any situation where I can reuse "ArticleSchema"?
It's designed that way so that you can define a schema for subdocuments, which do not map to distinct models. Keep in mind that a there is a one-to-one relation between collections and models.
From the Mongoose website:
var Comments = new Schema({
title : String
, body : String
, date : Date
});
var BlogPost = new Schema({
author : ObjectId
, title : String
, body : String
, buf : Buffer
, date : Date
, comments : [Comments]
, meta : {
votes : Number
, favs : Number
}
});
var Post = mongoose.model('BlogPost', BlogPost);
Yeah sometimes I split the Schema's up into separate files and do this kind of thing.
// db.js
var ArticleSchema = require("./ArticleSchema");
mongoose.Model("Article", ArticleSchema);
It's only really useful when you have a bunch of static and other methods on models and the main model file gets messy.
Related
Allora, I'm using mongoose for the first time and I decided to create 2 schemes: the first one represents a user and the second one represents his enquires. Users have an array of enquires like:
var userSchema = new mongoose.Schema({
name: String,
enquires: { type : [Enquire.schema] , "default" : [] },
});
var enquireSchema = new mongoose.Schema({
status: {type: String, 'default': 'pending'},
enquire: String,
});
I see that if I search for an enquire and update its status, it doesn't update the same enquire on the user's array, meaning that they are different object. I don't want to save an array of IDs as it will be the same as a relational database, so I see only 1 solution which is forgetting about the enquire scheme and use only the User scheme. Is it the way mongoose works? For every relationship do I have to insert everything like nested object?
I think you should use references to achieve what you want to achieve.
For more information on mongoose references and populate see Mongoose Populate documentation.
Try this, It may help you.
User Schema :
var userSchema = new mongoose.Schema({
name: String,
enquires: [{ type : mongoose.Schema.Types.ObjectId , ref : 'Enquiry' }]//array of enquiries
});
var User = mongoose.model('User',userSchema );
module.exports = User;
Enquiry Schema :
var enquireSchema = new mongoose.Schema({
status: {type: String, 'default': 'pending'},
enquire: String,
});
var Enquiry = mongoose.model('Enquiry',enquireSchema );
module.exports = Enquiry ;
Working :
create a new Enquiry.
Push it's ID(_id) into user's enquires array.
var enquiry = new Enquiry();
enquiry.enquire = "Dummy enquiry";//set the enquiry
enquiry.save(function(err,result){
if(!err){
//push 'result._id' into users enquires array
}
});
whenever you update an enquiry, it will be automatically updated in
user's document.
use populate to retrieve user's enquiries.
You can embed sub documents (entity) which has id and is like a document or embed native array like a normal property.
And I think the correct definition for yours is :
var enquireSchema = new mongoose.Schema({
status: {type: String, 'default': 'pending'},
enquire: String,
});
var userSchema = new mongoose.Schema({
name: String,
enquires: { type : [enquireSchema] , "default" : [] },
});
If you use refs in embedded link then there are two separate collections and be like relational db's.
I use Mongoose and Passport in my web application for the addition of new users into my MongoDB database. I use Google oauth for registering/signing in. In my user schema, I have the following defined for the google method:
//user.js
var userSchema = mongoose.Schema({
google : {
id : String,
token : String,
access_token : String,
email : String,
name : String,
picture : String,
nameInfo : Object,
}
});
I use the following method for user creation:
//passport.js
var newUser = new User();
//newUser.google.token = token;
newUser.google.name = profile.displayName;
newUser.google.nameInfo = profile._json.name
newUser.google.email = profile.emails[0].value;
newUser.google.id = profile.id;
newUser.google.picture = profile._json.image.url + '0';
newUser.google.access_token = token;
You can see that all this data goes under the "google" array in the top level of my user document. How would I add a new, complex, static array? For example, I want a new array at the top level of document in the following format:
newUser.dogs = ["cats":[]}]
I need this particular format based on a dependency in how users should look in my web code. I will eventually be adding data to the "cats" array, but it needs to start out empty. When I try varations of this, I'm only able to get the top level array - ex: my document looks like:
objectid: 1000,
google: [...],
dogs: []
when I need it to look like:
objectid: 1000,
google: [...],
dogs: [{"cats":[]}]
What do I need to change to my schema, either on the schema design, or the data going into the schema?
You want to set inner embedded docs.
Here it is sample, You can create it like this.
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var Trigger = new Schema({
type : {type: String},
value: {type: Number}
});
var Field = new Schema({
label : {type: String},
type: {type: String},
triggers: [Trigger]
});
var Form = new Schema({
fields : [Field],
user_id : {type: String}
});
My mongo record is like this:
{
"_id":{"$oid":"5550b6de437f572112a29f1a"},
"cv_count":177732,
"gender_info": {"male_count": 50, "female_count": 32}
"stability_info_list":[{"ratio":8.802558610369414e-05,"total_count":34081,"years":0},{"ratio":5.868372406912943e-05,"total_count":34081,"years":1}],
"zhineng_id":"IT Manager"
}
I write the schema like this:
var ZhinengGenderSchema = new Schema({
male_count: Number,
female_count: Number
});
var ZhinengStabilitySchema = new Schema({
ratio: Number,
total_count: Number,
years: Number
});
var ZhinengStats = new Schema({
cv_count: Number,
gender_info: ZhinengGenderSchema,
stability_info_list: [ZhinengStabilitySchema],
zhineng_id: String
})
But I got this excetion:
TypeError: Undefined type `undefined` at `gender_info`
Did you try nesting Schemas? You can only nest using refs or arrays.
so mongoose doesn't support nest schemas? But my database has already been there, I cannot change, so how can I define my schema?
Just don't create a new schema for the subdocuments and you should be fine, i.e.:
var ZhinengGenderSchema = {
male_count: Number,
female_count: Number
};
var ZhinengStabilitySchema = {
ratio: Number,
total_count: Number
years: Number
};
var ZhinengStats = new Schema({
cv_count: Number,
gender_info: ZhinengGenderSchema,
stability_info_list: [ZhinengStabilitySchema],
zhineng_id: String
})
With mongoose you can define nesting (embedded) schemas in Array, like this:
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var bookSchema = new Schema({
value: { type: String }
});
var authorSchema = new Schema({
books: [bookSchema]
});
Or by reference
var mongoose = require('mongoose'),
Schema = mongoose.Schema,
ObjectId = mongoose.Schema.Types.ObjectId;
var auhtorSchema = new Schema({
book: { type: ObjectId, ref: 'Book'}
});
You may choose what is more appropriate for you
As far as I know, this is due to a current limitation of Mongoose. You cannot
declare a schema field to include a single sub-document: you have to use an array, instead. See this: https://github.com/Automattic/mongoose/pull/585
You can set up later the proper business logic in order to ensure that only one sub-element will be added.
Try this:
var ZhinengStats = new Schema({
cv_count: Number,
gender_info: [ZhinengGenderSchema],
stability_info_list: [ZhinengStabilitySchema],
zhineng_id: String
})
This way, each sub-document has got its own _id in MongoDB (even though it does not lie in a specific collection). See more: http://mongoosejs.com/docs/subdocs.html
You could also prefer something like this:
var ZhinengStats = new Schema({
cv_count: Number,
gender_info: [{male_count: Number, female_count: Number}],
stability_info_list: [ZhinengStabilitySchema],
zhineng_id: String
})
In this case, you nest a schema inside another. The single gender_info element does not have the dignity of a document.
I am going to implement the function like left join of mysql in mongoose.
the date is
var mongoose = require('mongoose')
, Schema = mongoose.Schema
var personSchema = Schema({
_id : Number,
name : String
});
var storySchema = Schema({
_creator : { type: Number, ref: 'Person' },
title : String
});
var personProfile = Schema({
userid : {type: Number, ref: 'Person'},
birthday: Date,
profilelink: String,
email: String
});
var Story = mongoose.model('Story', storySchema);
var Person = mongoose.model('Person', personSchema);
var personProfile = mongoose.model('Personprofile', personProfile );
I am going to display the Story model with the user profile.
We have to get the profile info with the _creator of story and the userid of personProfile
How can I get the info using mongoose query?
Thanks Nelis
What your are trying to do is not possible because there is no join statement on mongodb.
You can achieve this in two ways:
1 - By DBRefs: Changing your Schema to one that include all the user info and do not split them in two different schemas as you are doing, see denormalized. Then you can use the Population function to get all the persons data.
2 - By Manual references: The second solution is to make a second call to the database getting the personProfile data using the userid as a filter.
Example 1:
This way you can get all persons data without a second call to the database.
var personSchema = Schema({
_id : Number,
name : String,
birthday: Date,
profilelink: String,
email: String
});
var storySchema = Schema({
_creator : { type : Schema.Types.ObjectId, ref: 'Person' },
title : String
});
Story
.find()
.populate(['_creator'])
.exec(function(err, stories) {
//do your stuff here
}
Notice that I'm using the type Schema.Types.ObjectId and not the Number. This way, you can assign a new value to _creator passing either the _id or the person object and the mongoose will convert the object to its _id. For example, you can post something like
{
_creator : {
_id : 123123123123,
name : 'Foo',
birthday: '0000-00-00',
profilelink: 'http://foo.bar',
email: 'foo#bar.com'
},
title : 'Mr'
}
... and the mongoose will convert to
{
_creator : 123123123123,
title : 'Mr'
}
Example 2:
This way your data still normalized and you can get all the persons data with a second call.
Story
.find()
.exec(function(err, stories) {
var arrayLength = stories.length;
for (var i = 0; i < arrayLength; i++) {
var story = stories[i];
personProfile.findById(story._creator, function (err, person) {
story._creator = person;
}
};
// do your stuff here
}
I've seen many examples about mongoose and relations, but how can I create a reference to another entity into a custom field ?
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');
mongoose.connection.once('open', function(){
var Author = m.model('Author', new m.Schema({
name: String,
slugname: String
}));
var Book = m.model('Book', new m.Schema({
title: String,
author: {type: String, ref: 'Author.slugname'}
}));
});
In the code above, I'm linking Book.author into Author.slugname. it is just that I don't if this is the right way to do it.
No, you can't. Mongoose always use _id field to link documents. But...
You can set your own _id for each document, using any datatype you want. There are only two restrictions:
it should be unique
it should not be changed during document's lifetime
So, instead of adding new slugname field, use author's _id as a slugname:
var Author = m.model('Author', new m.Schema({
_id: String, // <-- slugname
name: String
}));
var Book = m.model('Book', new m.Schema({
title: String,
author: { type: String, ref: 'Author' }
}));
This is supported since Mongoose 4.5, and is called virtuals population.
Check my detailed answer on this (nearly duplicate) question.
Mongoose is set up more for direct object relations. Rather than linking your Book object to a slug for the Author object, it would suit better to link to the Author's _id property automatically created by Mongoose.
var Author = mongoose.model('Author', new mongoose.Schema({
name: String
});
var Book = mongoose.model('Book', new mongoose.Schema({
title: String
author: { type: mongoose.Schema.Types.ObjectId, ref: 'Author' }
});
You can then save an Author as the author of the Book object by either saving book.author = author or book.author = author._id. Mongoose will automatically serialize the data when saving.
var author = new Author();
author.name = 'Hank Brekke';
var book = new Book();
book.title = 'My Book';
book.author = author;
book.save();
When pulling the book object, you can have Mongoose automatically populate the author property, which by default it will not, by adding the .populate('author') modifier before calling .exec()
Book.findOne({ /* query */}).populate('author').exec(function(error, book) {
var author = book.author;
});
References:
http://mongoosejs.com/docs/populate.html