Develop Reference

MongoDB - Update or Insert object in array in C#

I have the following collection
{
"_id" : ObjectId("57315ba4846dd82425ca2408"),
"myarray" : [
{
userId : ObjectId("570ca5e48dbe673802c2d035"),
point : 5
},
{
userId : ObjectId("613ca5e48dbe673802c2d521"),
point : 2
},
]}
and I want to add a new element to this array in C#, Could please to help me I try to do it's by $push but always give me this error. thanks
MongoDB.Driver.AddToSetUpdateDefinition<TDocument, TItem>.Render(IBsonSerializer<TDocument> documentSerializer, IBsonSerializerRegistry serializerRegistry)`enter code here`

How to Append to a Field in MongoDB C# [duplicate]

I have a document with a field containing a very long string. I need to concatenate another string to the end of the string already contained in the field.
The way I do it now is that, from Java, I fetch the document, extract the string in the field, append the string to the end and finally update the document with the new string.
The problem: The string contained in the field is very long, which means that it takes time and resources to retrieve and work with this string in Java. Furthermore, this is an operation that is done several times per second.
My question: Is there a way to concatenate a string to an existing field, without having to fetch (db.<doc>.find()) the contents of the field first? In reality all I want is (field.contents += new_string).
I already made this work using Javascript and eval, but as I found out, MongoDB locks the database when it executes javascript, which makes the overall application even slower.

Starting Mongo 4.2, db.collection.updateMany() can accept an aggregation pipeline, finally allowing the update of a field based on its current value:
// { a: "Hello" }
db.collection.updateMany(
{},
[{ $set: { a: { $concat: [ "$a", "World" ] } } }]
)
// { a: "HelloWorld" }
The first part {} is the match query, filtering which documents to update (in this case all documents).
The second part [{ $set: { a: { $concat: [ "$a", "World" ] } } }] is the update aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline). $set (alias of $addFields) is a new aggregation operator which in this case replaces the field's value (by concatenating a itself with the suffix "World"). Note how a is modified directly based on its own value ($a).

For example (it's append to the start, the same story ):
before
{ "_id" : ObjectId("56993251e843bb7e0447829d"), "name" : "London
City", "city" : "London" }
db.airports
.find( { $text: { $search: "City" } })
.forEach(
function(e, i){
e.name='Big ' + e.name;
db.airports.save(e);
}
)
after:
{ "_id" : ObjectId("56993251e843bb7e0447829d"), "name" : "Big London
City", "city" : "London" }

Old topic but i had the same problem.
Since mongo 2.4, you can use $concat from aggregation framework.
Example
Consider these documents :
{
"_id" : ObjectId("5941003d5e785b5c0b2ac78d"),
"title" : "cov"
}
{
"_id" : ObjectId("594109b45e785b5c0b2ac97d"),
"title" : "fefe"
}
Append fefe to title field :
db.getCollection('test_append_string').aggregate(
[
{ $project: { title: { $concat: [ "$title", "fefe"] } } }
]
)
The result of aggregation will be :
{
"_id" : ObjectId("5941003d5e785b5c0b2ac78d"),
"title" : "covfefe"
}
{
"_id" : ObjectId("594109b45e785b5c0b2ac97d"),
"title" : "fefefefe"
}
You can then save the results with a bulk, see this answer for that.

this is a sample of one document i have :
{
"_id" : 1,
"s" : 1,
"ser" : 2,
"p" : "9919871172",
"d" : ISODate("2018-05-30T05:00:38.057Z"),
"per" : "10"
}
to append a string to any feild you can run a forEach loop throught all documents and then update desired field:
db.getCollection('jafar').find({}).forEach(function(el){
db.getCollection('jafar').update(
{p:el.p},
{$set:{p:'98'+el.p}})
})

This would not be possible.
One optimization you can do is create batches of updates.
i.e. fetch 10K documents, append relevant strings to each of their keys,
and then save them as single batch.
Most mongodb drivers support batch operations.

db.getCollection('<collection>').update(
// query
{},
// update
{
$set: {<field>:this.<field>+"<new string>"}
},
// options
{
"multi" : true, // update only one document
"upsert" : false // insert a new document, if no existing document match the query
});

MongoDb c# driver 2.0 bulk update error

I try to perform bulk update operation using Official Mongo c# 2.0 driver via the following code :
var query =
Builders<Profile>.Filter.In(p => p.userId, listBounce.Values.ToList()) &
Builders<Profile>.Filter.In(p => p.ID, listBounce.Keys.Select(x=> new ObjectId(x)).
ToList());
var update = Builders<Profile>.Update.Set(p => p.MailLists[-1].Status, (int)wrongEmailStatusAssetId);
dbCollection.UpdateManyAsync(query, update).Wait();
But there is the following error has been occurred
{"A write operation resulted in an error.\r\n
The positional operator did not find the match needed from the query.
Unexpanded update: p2l.$.status"}
I need to update each element's property in array which matches the query.
The documents structure is :
{
"_id" : ObjectId("55eeb5da965bb036984110b9"),
"created" : ISODate("2015-09-08T10:17:59.784Z"),
"userId" : 13929,
"email" : "go-get#yandex.ru",
"firstName" : "Skrillex",
"lastName" : "Skrillex",
"phoneNumber" : "",
"isUnsubscribed" : false,
"isAboveLimit" : false,
"status" : 0,
"userAgent" : 9760,
"isDeleted" : false,
"p2l" : [
{
"listId" : 45165,
"status" : 131,
"subscriptionDate" : ISODate("2015-09-04T06:24:55.763Z")
}
]
}

Just add Builders<Profile>.Filter.Exists(p=>p.MailLists) to query and the issue could be solved.

Find an specific element in a MongoDB document from C#

I am trying to access MongoDB from C# ASP.NET application.
Let's assume, I've a document like below-
{
"_id" : ObjectId("546c776b3e23f5f2ebdd3b03"),
"Name" : "Test",
"Values" : [
{
"Name" : "One",
"Value" : 1
},
{
"Name" : "Two",
"Value" : 2,
"Parameters": [{"Type": "Type A"}, {"Type": "Type B"}]
}
]
}
Please note that, only the _id and Name elements are fixed; other elements are dynamically created by the user where both the key and value are defined by the user.
Now, I would like to search for the element Type with the value Type A. How can I do this from a MongoDB C# driver?

You can use this code:
var query = Query.EQ("Values.Parameters.Type", "Type A");
var items = collection.Find(query).ToList();
If you data has structure use this:
var items = collection.FindAs<Item>(query).ToList();
Edit:
For dynaically search the only way comes to my mind is full-text-search:
Step1: Define a full text-search on all fields via db.test.ensureIndex({"$**" : "text"});
Step2: Search your query db.test.find( { $text: { $search: "Type A" } } )
If its your answer, the C# code should be easy.

Below aggregation query may solve your problem but I don't know how to write this in C#
db.collectioName.aggregate({"$unwind":"$Values"},
{"$unwind":"$Values.Parameters"},
{"$match":{"Values.Parameters.Type":"Type A"}},
{"$group":{"_id":"$Values"}})

Insert in to a nested array Using C# Official Driver MongoDB

Here is my exact schema:
{
"_id" : ObjectId("4fb4fd04b748611ca8da0d48"),
"Name" : "Categories",
"categories" : [{
"_id" : ObjectId("4fb4fd04b748611ca8da0d46"),
"name" : "Naming_Conventions",
"sub-categories" : [{
"_id" : ObjectId("4fb4fd04b748611ca8da0d47"),
"name" : "Namespace_Naming",
"standards" : []
}]
}]
}
As you can see I have an array named "standards" nested way down in there. How would I programmatically insert in to that using the C# driver? I have tried all of the examples I have found online but none of them are working.

Something like the below. Obviously, if any of these are not present on the way down to it, you're going to get a null reference exception.
var doc = collection.FindOne(Query.EQ("_id", new ObjectId("4fb4fd04b748611ca8da0d48")));
var standards = doc["categories"]
.AsBsonArray[0]
.AsBsonDocument["sub-categories"]
.AsBsonArray;
standards.Add(new BsonDocument());
collection.Save(doc);