I'm trying to get all documents in a collection based on a subdocument array values. This is my data structure in the collection i'm seeking:
{
_id: ObjectId('...'),
name: "my event",
members:
[
{
_id: ObjectId('...'),
name: "family",
users: [ObjectId('...'),ObjectId('...'),ObjectId('...')]
},
{
_id: ObjectId('...'),
name: "work",
users: [ObjectId('...'),ObjectId('...'),ObjectId('...')]
}
]
}
I should point out that the schema of these objects are defined like so:
Events:
{
name: { type: String },
members: {type: [{ type: ObjectId, ref: 'MemberGroup' }], default:[] }
}
MemberGroup:
{
name: { type: String },
users: [{type: mongoose.Schema.Types.ObjectId, ref: 'User'}]
}
and of course User is just an arbitrary object with an id.
What i'm trying to fetch: i want to retrieve all events which has a specific user id in its member.users field.
i'm not sure if its event possible in a single call but here is what i've tried:
var userId = new mongoose.Schema.ObjectId('57d9503ef10d5ffc08d6b8cc');
events.find({members: { $elemMatch : { users: { $in: [userId]} } }})
this syntax work but return no elements even though i know there are matching elements (using robomongo to visualize the db)
So after a long search in stackoverflow i came across the good answare here:
MongoDB: How to find out if an array field contains an element?
my query changed to the following which gave me my desired result:
var userId = new mongoose.Schema.ObjectId('57d9503ef10d5ffc08d6b8cc');
events.find({}, {members: { $elemMatch : { users: { $eq: userId} } }})
notice the use of the second find parameter to specify the query limit instead of the first one (which is odd)
Related
Am I able to check a value from other mongo schema while findAndUpdate?
Example:
Schema 1:
{ _id: 'myId1', name: 'test' }
Schema 2:
{ _id: 'myId2', name: 'test-rest', connectedId: [ 'myId1' ] }
Now I want to check if connectedId has value name while updating
await MongoModel.findOneAndUpdate(
{
_id: "myId",
connectedId: { connectedValue.name === 'test' } // Now I want check if value from this connectedId has a value equal to my value
},
{
name: "changeName"
}
)
EDIT: I completely overlooked that you also wanted to update the referenced document. I will howeever leave this answer in case someone else finds it useful.
You should checkout populate from Mongoose documentation. You can add references to other models like this when defining your schema:
connected: [{ type: Schema.Types.ObjectId, ref: 'OtherModelName' }]
OtherModelName should match with however you name your other model when calling mongoose.model('OtherModelName', yourSchema); After that, you can populate the field with some conditions. This example is from the aforementioned documentation:
Story.
find().
populate({
path: 'fans',
match: { age: { $gte: 21 } },
// Explicitly exclude `_id`
select: 'name -_id'
}).
exec();
In your case, it would be something like
YourModel
.find()
.populate({
path: 'connected',
match: {name: 'test'}
})
.exec();
I need to define the mongoose schema for for nested documents which is given below.
Documents:
"Options":[{"Value":["28","30","32","34","36","38","40","42","44","46"],"_id":{"$oid":"5de8427af55716115dd43c8f"},"Name":"Size"},{"Value":["White"],"_id":{"$oid":"5de8427af55716115dd43c8e"},"Name":"Colour"}]
I was declaring like below but its not working.
const Product = new Schema(
{
Options: [{ value: { _id: ObjectId, Name: String } }]
},
{
timestamps: {
createdAt: "createdAt",
updatedAt: "updatedAt"
},
collection: "products"
}
);
Here I need the schema where if i will directly add/update the same document then it will be added.
You need to modify your schema like this :
{
Options: [ new Schema ({ value: [...], _id: Schema.Types.ObjectId, Name: String })]
}
This is the way to create an array of subdocuments with Mongoose. If you don't use the "new Schema" key words, you are actually creating a field with type "Mixed", which needs a different way to handle updates.
You can also omit the _id, it should be added automatically.
You can find more information on subdocument on this page :
https://mongoosejs.com/docs/subdocs.html
...and on mixed type fields : https://mongoosejs.com/docs/schematypes.html#mixed
...which will explain shortly the problem.
{
Options: [ new Schema ({ _id: mongoose.Types.ObjectId(),value: [String], Name: String } })]
}
So basically I need to filter my data with my own filter, which is array of strings, but problem is, that that exact field is inside nested object in array in DB. so, part of my Schema looks like this:
members: [
{
_id: { type: Schema.Types.ObjectId, ref: "Users" },
profilePicture: { type: String, required: true },
profile: {
firstName: { type: String },
lastName: { type: String },
occupation: { type: String },
gender: { type: String }
}
}
]
and my filter looks like this
gender: ["male","female"]
expected result with this filter is to get a team which has both male users and female users, if it has only male, or only female, it should not give me that team. but everything i've tried was giving me everything what included males and females even tho there were only male members.
what i've tried:
db.teams.find(members: { $elemMatch: { "profile.gender": { $in: gender } } })
This works only when there is one gender specified in the filter, and well, i know it must not work on what i am trying to achieve, but i dont know how to achieve it. any help will be appreciated
Edit: I've tried to do it in this way
db.teams.find({
$and: [
{ members: { $elemMatch: { "profile.gender": gender[0] } } },
{ members: { $elemMatch: { "profile.gender": gender[1] } } }
]
})
and this gives me result only when both filters are specified, however, if there is only one filter(either "male", or "female") it is giving me nothing.
Use $and operator instead of $in.
db.teams.find(members: {$elemMatch: {$and: [{'profile.gender': 'male'}, {'profile.gender': 'female'}]}})
This query works no matter how many elements you want to compare
db.teams.find({$and: [{'members.profile.gender': 'male'}, {'members.profile.gender': 'female'}]})
You need to dynamically generate the query before passing it to find, if you want to cover more than one case.
You can do this with the $all operator that finds docs where an array field contains contains all specified elements:
var gender = ['male', 'female'];
db.teams.find({'members.profile.gender': {$all: gender}});
I have the following schema:
var lessonSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: String,
students: [{
_id: mongoose.Schema.Types.ObjectId,
attendance: {
type: Boolean,
default: false,
},
}],
});
The students array is an array of students who attended the particular lesson. I want to find a lesson using whether a particular user is present in the students array and then sent only that element of the students array which corresponds to the user making the request, along with all other fields as it is. For example, the query should return:
{
_id: 'objectid',
name: 'lesson-name'
students: [details of just the one student corresponding to req.user._id]
}
I tried using:
Lesson.find({'students._id': String(req.user._id)}, {"students.$": 1})
The query returns the document with just the id and the relevant element from the students array:
{
_id: 'objectid'
students: [details of the one student corresponding to req.user._id]
}
I tried using:
Lesson.find({'students._id': mongoose.Types.ObjectId(req.user._id)})
This returns the document with the details of all the students:
{
_id: 'objectid',
name: 'lesson-name'
students: [array containing details of all the students who attended the lesson]
}
How can I modify the query to return it the way I want?
You can return the name field by adding it to the projection object like this:
Lesson.find({ "students._id": String(req.user._id) }, { "name": 1, "students.$": 1 })
When you add a projection object (2nd parameter to find), the _id field is returned by default, plus whichever fields you set to 1.
Therefore, you were returning just the _id and the desired student but not the name field.
If you want to return all other fields and just limit the array to the matched item then you can make use of $slice in your projection:
Lesson.find({ "students._id": String(req.user._id) }, { "students.$": { $slice: 1 } })
I need some help with MongoDb. I need to check if an object exists in the database. If it's true, then I need to check if this object has a specific element into array (Products). If not, I need to create this object(Order) with this element(Cookie) in to array(Products).
Example data:
Order {
_id: ObjectId("580bc55f54101f1d18152d88"),
code: "AVG223424",
products: [
{
name: "Cookie"
},
{
name: "Soda"
}
]
}
Finally, what is the better implementation?
Assuming you are using a collection with the name 'Orders'
db
.Orders
.update({
code: "12345"
}, {
$addToSet: {
products: {
name: "Cookie"
}
},
$setOnInsert: {
code: "12345"
}
}, {
upsert: true
});
This query looks for a document with the same 'code,' and if found, will add the object '{name: "Cookie"}' if there is no other Object with the same key/val pairs. If the document does not exist, the '$setOnInsert' command will set the specified fields only if a new document is created.