I'm fairly new to this, so bear with me, however I have 2 collections. One called photos and another called users.
In Node, I am taking the data and putting it into my MongoDB using mongoose. I've got this working fine with my Schema:
var picSchema = new Schema({
uid: String,
pid: String,
oFile: String
});
What I want to do though is for the uid, I want to add the ObjectId for the user uploading the photo. I can pass this as a String, however I thought that I would have had to have the field set as an ObjectId, but seems I cannot do this?
Unless I am missing something, I might as well just add the username in there and use that as a reference?
Use mongoose.Schema.Types.ObjectId to populate the field with an ObjectId. In this case, you would use User (or whatever the name of your User schema is).
var picSchema = new Schema({
uid: {type: mongoose.Schema.Types.ObjectId, ref: 'User'},
pid: String,
oFile: String
});
Further to this, you can also use the Mongoose method Populate if you wish to expand the User document within a Pic document. For example:
Pic.find({})
.populate('uid')
.exec(function(err, pic) {
console.log(pic);
// do something
});
Related
i want to define the schema dynamically according to the condition using mongoose
Schema
new mongoose.Schema({
type: String, //BASIC OR ADVANCE
// only for type = BASIC
name: String,
age: Number
/*
want these fields too but only if type = ADVANCE
email: String,
password: Number
PhoneNumber: String
*/
});
how would i achieve this kind of schema using mongoose.
it depends on what your approach to your database is. you can simply create two types with identifiers as Advance and Basic and use middleware to maintain the flow. Now to answer your question:
something like:
new mongoose.Schema({
type: String, //BASIC OR ADVANCE
// only for type = BASIC
name: String,
age: Number,
advance: []
And now you can check if advance is empty or not. Seriously it all depends on your approach, how you deal with the problem. Once a Schema is declared you can without the advance field, you can still save data like:
const MyModel = mongoose.model('Test', new Schema({ name: String }));
const doc = new MyModel();
doc.advance = {
email: "test#test.com",
password: 1234,
PhoneNumber: 1234
}
doc.save();
But with this structure if you want to know the Schema, you'll think that in your file it is only name and age and later when you start exploring, you'll find out that you are doing something like this and using a proper structure.
Think of moongoose documents as JavaScript Objects, there is a reason it is known as non-Structured data. Hope this explanation helps.
Not sure if this is good/bad practice but I have successfully serverd two sets of data (mongodb collections) to a jade page.
examples of these data mongoose Schemas are the following:
...
var personSchema = new Schema({
firstName: String,
lastName: String,
email: String,
city: String,
state: String,
zip: Number
});
module.exports = mongoose.model('person', personSchema);
and
...
var personQuoteSchema = new Schema({
_person : {
type: Schema.ObjectId,
ref: 'person'
},
quote: Number
});
module.exports = mongoose.model('quote', personQuoteSchema);
I have successfully served both collections to the jade tpls and they work fine. But now i'm confused for how to do what i'm trying to do:
I am building a page for the quotes that pulls in data for the person the quote is for. In the document for a single quote from the quotes collection, it has the ObjectId of the person from the persons collection.
This is what I have so far, but i'm stuck:
each quote in quotes
ul
li #{quote.quote}
li #{quote._person.firstName} #{quote._person.lastName}
Because it doesn't work. I need to find a way to go into the person document referenced in the quote document and get the firstName and lastName.
This is my first time asking for help on stackoverflow, please let me know if i'm missing anything that could help you help me.
The problem is that there's an extra step beyond just adding the ObjectId and ref into the Schema. As pointed out by #Molda, you have to use the .populate() function to make this work.
Once I saw the comment, I looked up the .populate() function, and this page does a great job explaining it.
So when I make the call, it has to look something like:
quote.find({}).populate({
path: '_person',
model: 'person'
}).exec(callback);
In my application I have a User Collection. Many of my other collections have an Author (an author contains ONLY the user._id and the user.name), for example my Post Collection. Since I normally only need the _id and the name to display e.g. my posts on the UI.
This works fine, and seems like a good approach, since now everytime I deal with posts I don`t have to load the whole user Object from the database - I can only load my post.author.userId/post.author.name.
Now my problem: A user changes his or her name. Obviously all my Author Objects scattered around in my database still have the old author.
Questions:
is my approuch solid, or should I only reference the userId everywhere I need it?
If I'd go for this solution I'd remove my Author Model and would need to make a User database call everytime I want to display the current Users`s name.
If I leave my Author as is, what would be a good way to implement a solution for situations like the user.name change?
I could write a service which checks every model which has Authors of the current user._id and updates them of course, but this sounds very tedious. Although I'm not sure there's a better solution.
Any pro tipps on how I should deal with problems like this in the future?
Yes, sometime database are good to recorded at modular style. But You shouldn't do separating collection for user/author such as
At that time if you use mongoose as driver you can use populate to get user schema data.
Example, I modeling user, author, post that.
var UserSchema = new mongoose.Schema({
type: { type: String, default: "user", enum: ["user", "author"], required: true },
name: { type: String },
// Author specific values
joinedAt: { type: Date }
});
var User = mongoose.model("User", UserSchema);
var PostSchema = new mongoose.Schema({
author: { type: mongoose.Scheam.Types.ObjectId, ref: "User" },
content: { type: String }
});
var Post = mongoose.model("Post", PostSchema);
In this style, Post are separated model and have to save like that. Something like if you want to query a post including author's name, you can use populate at mongoose.
Post.findOne().populate("author").exce(function(err, post) {
if(err)
// do error handling
if(post){
console.log(post.author.type) // author
}
});
One solution is save only id in Author collection, using Ref on the User collection, and populate each time to get user's name from the User collection.
var User = {
name: String,
//other fields
}
var Author = {
userId: {
type: String,
ref: "User"
}
}
Another solution is when updating name in User collection, update all names in Author collection.
I think first solution will be better.
I'm stuck with mongoose populate returning null. I have a very similar situation to another question where it seems to we working just fine, perhaps with one important difference:
The model I'm referencing only exist as a subdocument to another model.
Example:
// The model i want to populate
Currency = new Schema({
code: String,
rate: Number
});
// The set of currencies are defined for each Tenant
// A currency belongs to one tenant, one tenant can have multiple currencies
Tenant = new Schema({
name: String,
currencies: [Currency]
});
Product = new Schema({
Name: String,
_currency: {type: ObjectId, ref: 'Currency'},
});
Customer = new Schema({
tenant: {type: ObjectId, ref: 'Tenant'},
products: [ Product ]
});
Then I export the models and use them in one of my routes where what I would like to do is something like
CustomerModel.find({}).populate('products._currency').exec(function(err, docs){
// docs[0].products[0]._currency is null (but has ObjectId if not usinn populate)
})
Which is returning null for any given product._currency but if I don't populate i get the correct ObjectId ref, which corresponds to an objectId of a currency embedded in a tenant.
I'm suspecting I need currencies to be stand-alone schema for this to work., Ie not just embedded in tenant, but that would mean I get a lot of schemas referencing each other.
Do you know if this is the case, or should my set-up work?
If this is the case, I guess I just have to bite the bullet and have multitude of collections referencing each other?
Any help or guidance appreciated!
Is there a way for checking if a reference document id exists in the array field of its "parent" model?
Imagine you know the objectId you want to check if exists because you don't want duplicates and also want to avoid that an error was thrown when trying to insert it.
I would like to know if there is an elegant and simple way as the method mongoose provides when working with subdocuments: var doc = car._components.id(theComponentIdIWantToCheck)
In this case it is a reference document:
Example:
// Car.js
var CarSchema = new Schema({
name: String,
description: String,
_components: [ { type: Schema.Types.ObjectId, ref: 'Component'},]
});