I have a document object that has an embedded sub-document.
To "clear" the sub-document, I try this:
obj.mysub = {};
obj.save();
This doesn't work, my object still has the contents of the mysub sub-document.
But this:
obj.mysub = undefined;
obj.save();
This does work, it removes my sub-document from the object.
My question is why doesn't the first version work? What is going on in Mongodb / Mongoose in the first example?
[edit] Why doesn't the empty object get saved in the first example above.
Mongoose sort of "protects" you from a lot of logic like you have presented in it's own internal resolution. So if you actually need to do this then do it at a lower level to the driver as in:
YourModel.update(
{ /*statement matching your document as a query */ },
{ "$unset": { "mysub": 1 } }
)
And per the normal MongoDB logic then this will work and remove that level in the document that was selected. See the $unset operator for more.
Related
Background:
I have an array (A) of new objects that need to be added to an array field in Mongoose. if successful it should print to screen the newly updated object but it prints null. I checked the database and confirmed it also does not update at all. I followed the docs to use the $push and $each modifiers here:
https://www.mongodb.com/docs/manual/reference/operator/update/each/
Desired Behaviour:
I would like each object in (A) to be added to the Array field, not (A) itself. Upon success, it should print to screen the newly updated object.
Attempted Approach:
let identifier={customer:{external_id:'12345'}}
let array = [{value:30},{value:30}]
User.findOneAndUpdate(identifier,{$push:{points:{$each:array}}},{new:true})
.then((result)=>{
console.log(result)
})
Attempted Resolutions:
I tested if the issue was with the identifier parameter, but it works fine when the update parameter does not have $each (i.e. it pushes the whole array (A) into the array field)
I thought about using $addToSet like in the solution below, but as you can see in the sample code above, I want to push all objects even if they are not unique:
Mongoose - Push objects into nested array
use dot "." notation for embedded field
let filter={'customer.external_id':'12345'}
let array = [{value:30},{value:30}];
let update = { $push: { points: { $each: array } } };
User.findOneAndUpdate(filter,update,{new: true})
.then((result)=>{
console.log(result)
})
It turns out the IDs did not match. There was no issue with the code. Sorry guys.
I got a generic GET function that worps for my entire app, considering I am using just absolute documents.
Now I get to a point that I need some properties of some of my documents reference others, and when executed, the GET function populate them (obviously). For that, I need to require the referenced schema, and populate with referenced model.
The point is: I want to my GET function stay generic, so I don't want to reference any of my schemas, unless it is needed. The same goes for the .populate() method.
To achieve that, I am iterating through each key of the resulting object of the .findOne() method, and trying to check if each specific key, is or is not a ObjectId/reference or not. something like this:
require('../schemas/mySchema').findOne({'slug': req.params.slug}, function(err, doc){
console.log(mongoose.Types.ObjectId.isValid(doc[key]));
});
But the only true value it returns is for the "id"and "__v" properties (no idea where these came from... I did not set them. _id is also false), all the rest comes as false (including a given property that IS a reference, tested and working)
Is there any way to do that?
Thanks in advance
I believe mongoose returns references with the objectId nested - in the same structure as a populated object but having only the _id key. Try this:
var item = doc[key];
if (typeof item === 'object') {
console.log(mongoose.Types.ObjectId.isValid(item._id));
}
I am attempting to perform a relatively simple update using Mongoose:
var location = locationService.getLocation(typedLat, typedLong, travelRadius);
DocumentModel.update({_id : passedInId }, { location : location }, function(err, resp){
next(err, resp);
});
In this case passedInId is the string:
"561ee6bbe4b0f25b4aead5c8"
And in the object (test data I created) the id is:
"_id": ObjectId("561ee6bbe4b0f25b4aead5c8")
When I run the above however, matched documents is 0. I assume this is because passedInId is being treated like a string, however when I type it to an ObjectId:
var queryId = ObjectId(passedInId)
The result is the same, the document doesn't match. What am I missing? This seems like it should be obvious....
Mongoose will correctly interpret a string as an ObjectId. One of the following must be the case:
That record is not in the collection. Run a query in the mongo shell to check.
Mongoose I'd looking in collection other than the one containing your test data. Remember, by default, mongo will lowercase the name under which you register your model and will add an a "s" to it.
Lastly, and your answer speaks to this, maybe your model it's just not being updated with any new information.
This behavior was because I had not yet updated the model in mongoose to include the location element. There is no error, it just doesn't match or do anything.
ASchema={item:[BSchema]};
ASchema.findOne({item._id=xx})
It gets a array of BSchema, document.item is a array. how to get only one item which _id is xx?
You want the positional $ operator using query projection to just return your matched array element. For Mongoose you can do this:
ASchema.findOne({"item._id": itemId},"item.$",function(err,doc) {
console.log( doc );
});
Or paired in an object:
ASchema.findOne({"item._id": itemId},{ "item.$": 1 },function(err,doc) {
console.log( doc );
});
Mongoose supports the shorthand syntax with options like "-fieldname" for field removal which is the same as { "fieldname": 0 }. But you cannot mix inclusion and exclusion with the exception of the root _id field.
Therefore you must specify all of the fields you want to appear when using projection.
See also .select() in the mongoose documentation.
I think your syntax for the query is wrong. Try:
ASchema.findOne({'item._id': xx})
This link is helpful for more examples: http://mongoosejs.com/docs/queries.html
How do you increment multiple fields in one query in mongoose?
For example, here is the working mongo query that I want to use with a mongoose model.
db.users.update({ userId:89 }, { $inc : { "subjectResults.attempts" : 1, "subjectResults.total_time" : 10, "subjectResults.total_score" : 100 } })
The above query is working in plain vanilla Mongo.
Edit: I have removed the confusing property name that lead to the comments below.
The APIs are nearly identical. Instead of db.users.update in straight mongodb, it's UserModel.update in mongoose. Pass in the exact same query and update options object.