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 })
Related
I'm using the request library to make calls from one sails app to another one which exposes the default blueprint endpoints. It works fine when I query by non-id fields, but I need to run some queries by passing id arrays. The problem is that the moment you provide an id, only the first id is considered, effectively not allowing this kind of query.
Is there a way to get around this? I could switch over to another attribute if all else fails but I need to know if there is a proper way around this.
Here's how I'm querying:
var idArr = [];//array of ids
var queryParams = { id: idArr };
var options: {
//headers, method and url here
json: queryParams
};
request(options, function(err, response, body){
if (err) return next(err);
return next(null, body);
});
Thanks in advance.
Sails blueprint APIs allow you to use the same waterline query langauge that you would otherwise use in code.
You can directly pass the array of id's in the get call to receive the objects as follows
GET /city?where={"id":[1, 2]}
Refer here for more.
Have fun!
Alright, I switched to a hacky solution to get moving.
For all models that needed querying by id arrays, I added a secondary attribute to the model. Let's call it code. Then, in afterCreate(), I updated code and set it equal to the id. This incurs an additional database call, but it's fine since it's called just once - when the object is created.
Here's the code.
module.exports = {
attributes: {
code: {
type: 'string'//the secondary attribute
},
// other attributes
},
afterCreate: function (newObj, next) {
Model.update({ id: newObj.id }, { code: newObj.id }, next);
}
}
Note that newObj isn't a Model object as even I was led to believe. So we cannot simply update its code and call newObj.save().
After this, in the queries having id arrays, substituting id with code makes them work as expected!
I understand how to embed documents in Mongoose, and they seem fairly straightforward if storing as arrays, for which the use case is fairly obvious:
var CommentSchema = new Mongoose.Schema({...});
var BlogPostSchema = new Mongoose.Schema({
comments : [CommentSchema],
});
But, what I don't see how to do after looking over the documentation forward and backward, is how to store a single sub-document that doesn't need or want to be in an Array.
var UserSchema = new Mongoose.Schema({...});
var BlogPostSchema = new Mongoose.Schema({
author: ??? // 'UserSchema' and UserSchema do not work here.
});
Is there any way to make this work? I don't want to just store the ObjectId, but rather, store a complete copy of the User record, but don't need or want an array.
You cannot embed schemas in this way, with the reasoning that those child docs would be confused with full documents, see this bug thread, where it is stated:
the reason we haven't added this support in the past is b/c this leaves us wondering if all pre-hooks will be executed the same way for the pseudo-child document as well as it implies that we can call save() on that child.
The answer here is to share not the schema, but just the definition.
var userdef = { name: String };
var UserSchema = new Schema(userdef);
var BlogPostSchema = new Schema({author: userdef});
This would result in a nested user object, without actually nesting the Schema.
Just sharing information doesn't support validation bubbling. And you may need validation of UserSchema also.
Instead I recommend array length validation
author: {type:[UserSchema], validate: function (arr) { return arr.length == 1 }},
UPDATE:
In case anyone comes across this now, as of Mongoose 4.2.0 single embedded subdocuments exist! :)
http://mongoosejs.com/docs/subdocs.html#single-embedded
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
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.
In previous versions of Mongoose (for node.js) there was an option to use it without defining a schema
var collection = mongoose.noSchema(db, "User");
But in the current version the "noSchema" function has been removed. My schemas are likely to change often and really don't fit in with a defined schema so is there a new way to use schema-less models in mongoose?
I think this is what are you looking for Mongoose Strict
option: strict
The strict option, (enabled by default), ensures that values added to our model instance that were not specified in our schema do not get saved to the db.
Note: Do not set to false unless you have good reason.
var thingSchema = new Schema({..}, { strict: false });
var Thing = mongoose.model('Thing', thingSchema);
var thing = new Thing({ iAmNotInTheSchema: true });
thing.save() // iAmNotInTheSchema is now saved to the db!!
Actually "Mixed" (Schema.Types.Mixed) mode appears to do exactly that in Mongoose...
it accepts a schema-less, freeform JS object - so whatever you can throw at it. It seems you have to trigger saves on that object manually afterwards, but it seems like a fair tradeoff.
Mixed
An "anything goes" SchemaType, its flexibility comes at a trade-off of
it being harder to maintain. Mixed is available either through
Schema.Types.Mixed or by passing an empty object literal. The
following are equivalent:
var Any = new Schema({ any: {} });
var Any = new Schema({ any: Schema.Types.Mixed });
Since it is a schema-less type, you can change the value to anything
else you like, but Mongoose loses the ability to auto detect and save
those changes. To "tell" Mongoose that the value of a Mixed type has
changed, call the .markModified(path) method of the document passing
the path to the Mixed type you just changed.
person.anything = { x: [3, 4, { y: "changed" }] };
person.markModified('anything');
person.save(); // anything will now get saved
Mongoose Schema Types
Hey Chris, take a look at Mongous. I was having the same issue with mongoose, as my Schemas change extremely frequently right now in development. Mongous allowed me to have the simplicity of Mongoose, while being able to loosely define and change my 'schemas'. I chose to simply build out standard JavaScript objects and store them in the database like so
function User(user){
this.name = user.name
, this.age = user.age
}
app.post('save/user', function(req,res,next){
var u = new User(req.body)
db('mydb.users').save(u)
res.send(200)
// that's it! You've saved a user
});
Far more simple than Mongoose, although I do believe you miss out on some cool middleware stuff like "pre". I didn't need any of that though. Hope this helps!!!
Here is the details description: [https://www.meanstack.site/2020/01/save-data-to-mongodb-without-defining.html][1]
const express = require('express')()
const mongoose = require('mongoose')
const bodyParser = require('body-parser')
const Schema = mongoose.Schema
express.post('/', async (req, res) => {
// strict false will allow you to save document which is coming from the req.body
const testCollectionSchema = new Schema({}, { strict: false })
const TestCollection = mongoose.model('test_collection', testCollectionSchema)
let body = req.body
const testCollectionData = new TestCollection(body)
await testCollectionData.save()
return res.send({
"msg": "Data Saved Successfully"
})
})
[1]: https://www.meanstack.site/2020/01/save-data-to-mongodb-without-defining.html
Note: The { strict: false } parameter will work for both create and update.
Its not possible anymore.
You can use Mongoose with the collections that have schema and the node driver or another mongo module for those schemaless ones.
https://groups.google.com/forum/#!msg/mongoose-orm/Bj9KTjI0NAQ/qSojYmoDwDYJ