What I'm trying to do should be straight forward but for some reason I'm having real difficulties figuring this out. I have the following Mongoose schemas (simplified).
var Status = new Schema({
name : { type: String, required: true },
description : { type: String }
});
var Category = new Schema({
statuses : [Status], // contains a list of all available statuses
// some other attributes
});
var Book = new Schema({
statuses : [Status], // preferably this would not be an array but a single document, but Mongoose doesn't seem to support that
// some other attributes
});
Now, I want to do the following:
Retrieve the Category document
Find a particular embedded Status document (based on request param)
Assign that particular embedded Status document to a particular Book document. I want to replace the existing Book status as at any given time there should only be one status set for a book.
Here is what I'm currently doing:
mongoose.model('Category').findOne({_id: id}, function(err, category){
if(err) next(err);
var status = category.statuses.id(statusId); // statusId available via closure
book.statuses[0] = status; // book available via closure; trying to replace the existing status here.
book.save(function(err){
if(err) next(err);
next();
});
});
The above seems to run fine and I don't get any errors. However, the new status is not saved to the document. Next time I output the updated Book document, it will still have the old status. I debugged this and the find() methods as well as setting the status seems to be fine.
The only thing I can think of right now is that somehow the status value I'm assigning is not in the right format to be saved with Mongoose. Although, I would expect some kind of error message then.
Or maybe there is a better way to do all of this anyway?
It could be because you are trying to copy an embedded document, which itself could have an ObjectId associated with it. Trying to save the duplicate Status within the Book would create two embedded documents with the same ObjectId. Try creating a new Status object and copying the fields.
It is hard to find docs on ObjectsIds for embedded documents, but they are mentioned here: http://mongoosejs.com/docs/embedded-documents.html.
Related
I am trying to add the ObjectId as a "Foreign key" to a collection. I have the previous id to link but I am having problem with the script.
Following is the script
db.users.find().forEach(function (user) {
var cursor = db.po1.find({"owner:": user.ID});
cursor.forEach(function(property) {
property.user_id = user._id;
db.po1.save(property);
});
});
The script runs but I do not get the field added to the documents of the po1 collection.
I am using mongoose for the api so I need the ObjectId. I do not want to embed the documents because of the rarity of the calls and the size of the po1 per user.
user.ID and po1.owner field are of the same type.
Thanks you for your time
From comment the answer.
Although save() has also been deprecated and finally the bellow script did the trick
db.users.find().forEach(function (user) {
var cursor = db.views.find({"user": user.ID});
cursor.forEach(function(object) {
object.userId = user._id;
db.views1.insertOne(object);
});
});
So through the innsert I created new collection and dropped previous.
How do you go about formatting the data response from mongoose? For a simple Post Schema
const postSchema = new mongoose.Schema({
title: {
type: String,
required: true,
}
},{
timestamps: true
});
Whenever I do a GET request to find all the post, It returns me all its fields including _id and __v in which I wouldn't want to return those fields in an API.
Is there a way I would select only certain fields that I would want to return?
As far as I've found was that I could set a second parameter of title onto my query and it would return only the _id and title.
const post = await Post.find({},'title');
I find the method above isn't the proper way to filter fields in cases in the future where the values are deeply nested object and we would like to pick out certain values.
Is there perhaps a way to create a Model/Class and pick the fields based on the Model/Class and return the respond?
You can use select from mongoose.
You can either select only the fields you want.
var find = await model.find({}).select("my_field")
Or not show the fields you don't want
var find = await model.find({}).select("-my_field")
Check the documentation
I am completely new to the fields of Mongoose and MongoDB.
I am currently trying trying to remove one element from my database.
This is my code so far:
My issueModel:
var mongoose = require('mongoose'); // loading module for mongoose
var db = mongoose.connect('mongodb://localhost/issuedb');
var issueSchema = new mongoose.Schema({
title: String,
description: String,
priority: String,
status: String
});
// Constructor Function:
var issueModel = mongoose.model('issues', issueSchema); // have to give the
name of the collection where the element should be stored + Schema
// Export this Construction Function for this Module:
module.exports = issueModel; // careful: module != model !
My post method for using the delete method:
// creating the router for deleting one item:
router.post('/delete/:id', (req, res) => {
console.log(req.params.id);
issueModel.remove({id: req.params.ObjectId})
.setOptions({ single: true }).exec(function (err, deleted) {})
.then(issues => res.render('issue', {issues: issues}));
The thing i would like to do here is using the object id - which is correctly stored in req.params.ObjectID according to my console.log, and deleting the corresponding object.
But currently , when i have got a table with about 3-4 entries, always the first one gets deleted. Why is that? I am really TOTALLY new and really tried searching a lot, but i could not find any solution until now. I am happy about any tips that would help me.
What am i doing wrong?
The ID in the URL and the Object.ID are the same! Why is the first object deleted then, not the second or the third?
I am hopeless right now.
I also read about the remove() option not being really used in todays time. But we were told at university to use this method right now.
I also tried findOneByID and delete methods i found in the mongoose database.
If you need any more code please let me know!
You can use one of the convenience methods for this: findByIdAndRemove:
issueModel.findByIdAndRemove(req.params.ObjectId, function(err) {
if (err) { ... failed }
});
This will remove a whole document matching the ID which I think its what you want, if you want to a remove property from a document that's a different query.
If you don't use one of the convenience methods which just take IDs (have ById in them), then you have to convert your ID from a string to an ObjectId:
const { ObjectId } = require('mongodb');
issueModel.remove({ id: ObjectId(req.params.ObjectId) }).setOptions({ single: true })
// in server.js
Meteor.publish("directory", function () {
return Meteor.users.find({}, {fields: {emails: 1, profile: 1}});
});
// in client.js
Meteor.subscribe("directory");
I want to now get the directory listings queried from the client like directory.findOne() from the browser's console. //Testing purposes
Doing directory=Meteor.subscribe('directory')/directory=Meteor.Collection('directory') and performing directory.findOne() doesn't work but when I do directory=new Meteor.Collection('directory') it works and returns undefined and I bet it CREATES a mongo collection on the server which I don't like because USER collection already exists and it points to a new Collection rather than the USER collection.
NOTE: I don't wanna mess with how Meteor.users collection handles its function... I just want to retrieve some specific data from it using a different handle that will only return the specified fields and not to override its default function...
Ex:
Meteor.users.findOne() // will return the currentLoggedIn users data
directory.findOne() // will return different fields taken from Meteor.users collection.
If you want this setup to work, you need to do the following:
Meteor.publish('thisNameDoesNotMatter', function () {
var self = this;
var handle = Meteor.users.find({}, {
fields: {emails: 1, profile: 1}
}).observeChanges({
added: function (id, fields) {
self.added('thisNameMatters', id, fields);
},
changed: function (id, fields) {
self.changed('thisNameMatters', id, fields);
},
removed: function (id) {
self.removed('thisNameMatters', id);
}
});
self.ready();
self.onStop(function () {
handle.stop();
});
});
No on the client side you need to define a client-side-only collection:
directories = new Meteor.Collection('thisNameMatters');
and subscribe to the corresponding data set:
Meteor.subscribe('thisNameDoesNotMatter');
This should work now. Let me know if you think this explanation is not clear enough.
EDIT
Here, the self.added/changed/removed methods act more or less as an event dispatcher. Briefly speaking they give instructions to every client who called
Meteor.subscribe('thisNameDoesNotMatter');
about the updates that should be applied on the client's collection named thisNameMatters assuming that this collection exists. The name - passed as the first parameter - can be chosen almost arbitrarily, but if there's no corresponding collection on the client side all the updates will be ignored. Note that this collection can be client-side-only, so it does not necessarily have to correspond to a "real" collection in your database.
Returning a cursor from your publish method it's only a shortcut for the above code, with the only difference that the name of an actual collection is used instead of our theNameMatters. This mechanism actually allows you to create as many "mirrors" of your datasets as you wish. In some situations this might be quite useful. The only problem is that these "collections" will be read-only (which totally make sense BTW) because if they're not defined on the server the corresponding `insert/update/remove' methods do not exist.
The collection is called Meteor.users and there is no need to declare a new one on neither the server nor the client.
Your publish/subscribe code is correct:
// in server.js
Meteor.publish("directory", function () {
return Meteor.users.find({}, {fields: {emails: 1, profile: 1}});
});
// in client.js
Meteor.subscribe("directory");
To access documents in the users collection that have been published by the server you need to do something like this:
var usersArray = Meteor.users.find().fetch();
or
var oneUser = Meteor.users.findOne();
I am not able to update my mongoose schema because of a CastERror, which makes sence, but I dont know how to solve it.
Trip Schema:
var TripSchema = new Schema({
name: String,
_users: [{type: Schema.Types.ObjectId, ref: 'User'}]
});
User Schema:
var UserSchema = new Schema({
name: String,
email: String,
});
in my html page i render a trip with the possibility to add new users to this trip, I retrieve the data by calling the findById method on the Schema:
exports.readById = function (request, result) {
Trip.findById(request.params.tripId).populate('_users').exec(function (error, trip) {
if (error) {
console.log('error getting trips');
} else {
console.log('found single trip: ' + trip);
result.json(trip);
}
})
};
this works find. In my ui i can add new users to the trip, here is the code:
var user = new UserService();
user.email = $scope.newMail;
user.$save(function(response){
trip._users.push(user._id);
trip.$update(function (response) {
console.log('OK - user ' + user.email + ' was linked to trip ' + trip.name);
// call for the updated document in database
this.readOne();
})
};
The Problem is that when I update my Schema the existing users in trip are populated, means stored as objects not id on the trip, the new user is stored as ObjectId in trip.
How can I make sure the populated users go back to ObjectId before I update? otherwise the update will fail with a CastError.
see here for error
I've been searching around for a graceful way to handle this without finding a satisfactory solution, or at least one I feel confident is what the mongoosejs folks had in mind when using populate. Nonetheless, here's the route I took:
First, I tried to separate adding to the list from saving. So in your example, move trip._users.push(user._id); out of the $save function. I put actions like this on the client side of things, since I want the UI to show the changes before I persist them.
Second, when adding the user, I kept working with the populated model -- that is, I don't push(user._id) but instead add the full user: push(user). This keeps the _users list consistent, since the ids of other users have already been replaced with their corresponding objects during population.
So now you should be working with a consistent list of populated users. In the server code, just before calling $update, I replace trip._users with a list of ObjectIds. In other words, "un-populate" _users:
user_ids = []
for (var i in trip._users){
/* it might be a good idea to do more validation here if you like, to make
* sure you don't have any naked userIds in this array already, as you would
*/in your original code.
user_ids.push(trip._users[i]._id);
}
trip._users = user_ids;
trip.$update(....
As I read through your example code again, it looks like the user you are adding to the trip might be a new user? I'm not sure if that's just a relic of your simplification for question purposes, but if not, you'll need to save the user first so mongo can assign an ObjectId before you can save the trip.
I have written an function which accepts an array, and in callback returns with an array of ObjectId. To do it asynchronously in NodeJS, I am using async.js. The function is like:
let converter = function(array, callback) {
let idArray;
async.each(array, function(item, itemCallback) {
idArray.push(item._id);
itemCallback();
}, function(err) {
callback(idArray);
})
};
This works totally fine with me, and I hope should work with you as well