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How to deal with C# object references in MongoDB?


How to deal with C# object references in MongoDB?

By : Ivar_H
Date : November 25 2020, 07:06 PM
I hope this helps you . I'm not an expert with MongoDB but I think in this scenario each of these items should be a separate collection with references to get the results you are after.
Meetings have a Group ID and a list of Person ID attendees. Groups have a list of Person ID members (people). If a person can only belong to one group then they can have a single group ID.
code :


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Are circular object references possible in mongoDB?

Are circular object references possible in mongoDB?


By : neo
Date : March 29 2020, 07:55 AM
seems to work fine Embedded documents aren't pointers to other documents, they are independent copies of data, so trying to create a self-referencing object through embedding would result in an infinite loop producing infinite data.
Links between MongoDB documents in form of DBRef's (Database References) are "soft". They don't actually have any meaning for the database itself. The database doesn't enforce them, doesn't check them for integrity and doesn't offer any support for following them.
what's the ideal way to deal with countries as a property on an object in mongoose (mongodb)

what's the ideal way to deal with countries as a property on an object in mongoose (mongodb)


By : Rebrand
Date : March 29 2020, 07:55 AM
should help you out Consider Mongoose Population:
code :
var mongoose = require('mongoose')
  , Schema = mongoose.Schema

// Job Schema
var jobSchema = Schema({
    name    : String, 
    country : { type: String, ref: 'Country' }  // To be populated
});

var countrySchema = Schema({
    _id   : String,
    name  : String,    
    lat   : Number,
    lng   : Number
});

var Country  = mongoose.model('Country', countrySchema);
var Job      = mongoose.model('Job', jobSchema);
Job.find().populate('country').exec(function (error, jobs) {
   // ...
});
Does mongoose / mongodb have access to object references in schema during aggregate?

Does mongoose / mongodb have access to object references in schema during aggregate?


By : Devesh Lohia
Date : March 29 2020, 07:55 AM
I hope this helps . there's no way to access object Referenced data during the aggregate Process, the work around I employed for my project was to add a reference to the owner in the schemas in question.
code :
User = new Schema({
    places:[{type: Schema.Types.ObjectId, ref:'Place'}],
    shouts:[{type: Schema.Types.ObjectId, ref:'Shout'}]
});
Place = new Schema({
    owner:{type: Schema.Types.ObjectId, ref:'Place'},
    name:String,
    description:String,
});
Shout = new Schema({
    owner:{type: Schema.Types.ObjectId, ref:'Place'},
    content:String,
});
module.exports.askForShoutInPlace = function(req, res){
var pname = new RegExp(req.params.pname, 'i'); 
var stringQ = new RegExp(req.paramos.qcontent, 'i');
Place.aggregate(
    [
       //find Places that match criteria
       {'$match':{'name':pname}},
       //select owner id object to result
       {'$project':{ owner:'$owner'}},
       //group those results to single array with unique ids of users
       {'$group':{_id:'$owner'}}
    ]).exec(function(err, results){
    //find user shouts that match string and belong to owners know to be owners of a place
    Shout.find({'content':stringQ}).where({'owner':{'$in':results}}).exec(function(err, shouts){
       res.send(shouts);
    });
});

}
Deal with Null object references through Interfaces

Deal with Null object references through Interfaces


By : Alice
Date : November 27 2020, 05:23 PM
To fix the issue you can do You could do it with a widening operator in SuperFoo that converts Foo to SuperFoo. As operators are Shared, you can return Nothing if the given Foo is Nothing, otherwise return a new SuperFoo.
code :
Public Shared Widening Operator CType(ByVal x As Foo) As SuperFoo
    Return If(x Is Nothing, Nothing, New SuperFoo(x))
End Operator
    Function TryGet(Name as String) as IFoo
        Return InitialTryGetFunction(Name) 'Converts into SuperFoo which is cast into IFoo
    End Function
    Function TryGet(Name as String) as IFoo
        Dim myResult As SuperFoo = InitialTryGetFunction(Name)
        Return myResult
    End Function
How does MongoDB deal with Object ID overlap when mongorestore?

How does MongoDB deal with Object ID overlap when mongorestore?


By : user3343737
Date : March 29 2020, 07:55 AM
Does that help MongoDB (standalone) is very bound in capacity compare to a cluster (shareds). If you want to increase insertion thoughput in the standalone mode you wont achieve much. If you throughput in multiple collections in a single standalone database is fine then it will be fine into a single collection. The second, insert + dump + insert is definitely slower than just insert in a single collection. So I recommend reconsider your solution. And yes, _id is an unique field by default, thus trying to insert multiple object with a sinle _id will cause an error.
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