I have a user profile, I have a field of 'earning' and it look like this in the schema
earning: {
type: Schema.Types.ObjectId,
ref: 'Earning'
}
This how do I make a default value for earning field when a new user is created? I can't do this
earning: {
type: Schema.Types.ObjectId,
ref: 'Earning',
default: 0
}
I got error of
Cast to ObjectId failed for value "0" at path "earning"
What you are doing wrong here is trying to cast a number on an ID field. Since it's a reference of another object Id field, you can not set 0 to it. What you need to do is to set null when a user is created in db and initialize it with a null value of earning.
Like:
earning: {
type: Schema.Types.ObjectId,
ref: 'Earning',
default: null
}
When instantiating a document based on a Schema which has a key of type 'ObjectId' and a ref to another collection, the only way that I've found to set a 'default' value is through the use of Mongoose middleware at the schema level as described here. For example, setting a comment's author to a default 'guest' document from a User collection when the author is not logged in might look like this:
// user document in MongoDB
{
_id: ObjectId('9182470ab9va89'),
name: 'guest'
}
// CommentSchema
const mongoose = require('mongoose')
const CommentSchema = mongoose.Schema({
author: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User',
},
body: String
})
CommentSchema.pre('save', function (next) {
this.author == null ? this.author = '9182470ab9va89' : null
next()
})
module.exports = mongoose.model('Comment', CommentSchema)
This example uses the 'save' pre hook with the ObjectId hardcoded in the schema for demonstration purposes, but you can replace the hardcoding of the ObjectId with a call to your backend or however else you'd like to get that value in there.
As I understand earning is indication of how much user earn so it should be of type Number not ObjectId
so try to change your Schema to be
earning: {
type: Number,
ref: 'Earning',
default: 0
}
so you can use 0
Note: if you should use ObjectId for some reason so the answer of 'Haroon Khan' is the correct answer.
Related
I have my Person schema like this :
const schema = new mongoose.Schema({
_id: Number,
name: String,
birthday: Date,
sex: String
});
schema.pre('findOneAndUpdate', async function (next) {
try {
let counter = await Counters.findByIdAndUpdate('person',
{
$inc: {
value: 1
}
},
{ new: true}
);
this._update._id = counter.value;
next();
}
catch (err) {
next(err);
}
});
The problem is when I try to add some new persons with findOneAndUpdate and upsert: true, it generates a CastError: Cast to ObjectId failed for value "18" at path "person".
My _id is defined as a Number so I don't understand why it's trying to cast it to an ObjectId ?
Update :
I found my problem, the Person model is referenced in some other model but I forgot to change the ref type in the other model...
person: {
type: Number, //HERE
ref: 'person',
required: true
}
You can change the type of the_id property although ins't a good approach, but actually you can't change the value since it's immutable and represents the primary key of the document. Keep in mind that _id is very important for MongoDB life cycle, like indexing. If you aim to change an Entity key, you can create other property, something like person_id.
_id is an auto generated property for MongoDB. If you want to add try a different name for the Id attribute like "personId" or you can use the auto generated Id by MongoDB without creating a seperate Id.
For my project i've created an userSchema which simplified looks like the following:
var userSchema = new Schema({
_id: String,
screenname: {type: String, required: false, default: "equal _id"},
});
The user has an _id that is a string which also is his username.
Everything works so far until i tried to add an extra field screenname. What i want is when the user creates an account, his screenname equals the value of _id. Later he can adjust it but by default it should equal the value of _id. i've also tried :
screenname: {type: String, required: false, default: _id},
But than ofcourse _id is not defined.
How should i set the default value to equal another value ?
use the pre middleware explained here
userSchema.pre('save', function (next) {
this.screenname = this.get('_id'); // considering _id is input by client
next();
});
You can pass a function to default, following is a schema field excerpt:
username: {
type: String,
required: true,
// fix for missing usernames causing validation fail
default: function() {
const _t = this as any; // tslint:disable-line
return _t.name || _t.subEmail;
}
},
Using mongoose populate:
http://mongoosejs.com/docs/populate.html
It seams that mongoose is forcing me to declare a ref value for populate when I first create the document but in my case i don't have the ref info yet. When I try to create a new document while providing an empty string I get to my developer field I get:
{"message":"Cast to ObjectId failed for value \"\" at path \"developer\"","name":"CastError","type":"ObjectId","value":"","path":"developer"}
Object that I'm saving through mongoose:
var Project = {
name: 'Coolproject',
status: 'pending',
developer: '',
type: 'basic',
};
Project.create(req.body, function(err, project) {
if(err) { return handleError(res, err); }
return
});
My Model:
var ProjectSchema = new Schema({
name: String,
status: {type:String, default:'pending'},
developer:{type: Schema.Types.ObjectId, ref: 'User'},
type:String
});
Basically I need to set it later, but it doesn't seam like this is possible. Currently my work around is populate it with a dummy user until later but this is less than desirable.
Thoughts?
Update
Realized that if i provide a object id like value (55132a418b3cde5546b01b37) it lets me save the document. Very odd. Guess it just figured it can find the document moves on. Wondering why this doesn't happen for a blank value.
The problem is explained in the error message. You cannot save an Empty String in the place of an ObjectId. The field is not listed as 'required', so there is no problem leaving it out and saving the document.
Code correction:
// you can save this
var Project = {
name: 'Coolproject',
status: 'pending',
type: 'basic',
};
You need to use the sparse index in model.
So, the valid model can have developer equal to nil
var ProjectSchema = new Schema({
name: String,
status: {type:String, default:'pending'},
developer:{type: Schema.Types.ObjectId, ref: 'User', sparse:true},
type:String
});
See
http://mongoosejs.com/docs/api.html#schematype_SchemaType-sparse and
http://docs.mongodb.org/manual/core/index-sparse/
for additional info
I have a photo model and every photo has a vehicle associated with it:
var ObjectId = mongoose.Schema.ObjectId;
var photoSchema = mongoose.Schema({
name: { type: String},
path: { type: String},
vehicle: { type: ObjectId, ref: 'Vehicle' }
});
What query can I perform to return all photos that match a given vehicle _id? I think the query looks the same as a normal find, but I'm not sure how to turn an _id into an ObjectId.
You don't need to turn anything, your ObjectId itself is _id but in string format when you send it through JSON to somewhere. Try following:
Photo.find({vehicle: id}, function(err, result){...});
Above id is just your vehicle's ObjectId obtained from any source e.g. User Interface
I'm currently trying to develop an app using mongo and node.js.
I am facing a problem when I want to build a query who use the populate option.
Here are my Schemas :
// Schema used by mongoose
var userSchema = new mongoose.Schema(
{
_id: mongoose.Schema.Types.ObjectId,
login: String,
password: String,
movies: [ { type: mongoose.Schema.Types.ObjectId, ref: movieModel} ],
admin: Boolean
},{ collection: "user" });
var movieSchema = new mongoose.Schema(
{
_id: mongoose.Schema.Types.ObjectId,
title: String,
}, { collection: "movie" });
As you can see, each user have an array of movies, this array contains valid ids of movies. What I want is to have the movies of an user. This is how I build my query :
var query = userModel.findOne({ login: req.session.user["login"] })
.populate("movies");
query.exec(function(err, user)
{
if (err)
throw err;
console.log(user.movies[0].title);
});
The query is executed successfully, but when I try to display the title of the first movie at the console.log line I got an error "TypeError: Cannot read property 'title' of undefined". I checked the documentation of mongoose and don't understand why I'm getting this error.
I would like to specify that my database contains valid data.
I put mongoose in debug mode, and this is the query that is executed :
Mongoose: user.findOne({ login: 'user' }) { fields: undefined }
Mongoose: user.find({ _id: { '$in': [ ObjectId("52e2a28949ad409834473e71"), ObjectId("52e2a28949ad409834473e79") ] } }) { fields: undefined }
The two ids on the second line are valid ids of movies. I would like to display their name.
Thanks a lot for your help.
What is the value of this: ref: movieModel?
movieModel would need to be set to the string like "Movie". See here for more information. It will need to match the identifier provided when you create the Movie model.
var Movie = mongoose.model('Movie', movieSchema);
So, you might have in a schema:
var userSchema = mongoose.Schema({
name: String,
favorite_movies: { type: Schema.Types.ObjectId, ref: 'Movie' }
});
var User = mongoose.model('User', userSchema);
I've used the string Movie in both the Schema definition and when creating the Movie type. They need to be exactly the same.
MongooseJs uses the string name of the Model to determine where to fetch the documents from when using ref and populate.
In the debug output, you can see how Mongoose is actually querying the wrong collection, as I'd expect it to be using movies.find to find the relevant Movie documents.