c# driver 2.5.0, Array filters for update operations

[Itzi Kagan]

Is there any documentation or examples on how to do it with the c# driver 2.5.0

Thanks,

Itzhak

[Wan Bachtiar]

Hi Itzhak,

Using the examples provided in MongoDB manual v3.6+ Specify arrayFilters for an Array Update Operations:

db.students.insert([
   { "_id" : 1, "grades" : [ 95, 92, 90 ] },
   { "_id" : 2, "grades" : [ 98, 100, 102 ] },
   { "_id" : 3, "grades" : [ 95, 110, 100 ] }
]);

To perform the same operation as below:

db.runCommand({
   update: "students",
   updates: [
     { q: { grades: { $gte: 100 } }, u: { $set: { "grades.$[element]" : 100 } }, arrayFilters: [ { "element": { $gte: 100 } } ], multi: true}
   ]
})

Using MongoDB .Net/C# Driver v2.5 the equivalent code example would be:

    var collection = database.GetCollection<BsonDocument>("students");

    var filter = Builders<BsonDocument>.Filter.Gte("grades", 100);
    var update = Builders<BsonDocument>.Update.Set("grades.$[element]", 100);

    var arrayFilters = new List<ArrayFilterDefinition>();
    ArrayFilterDefinition<BsonDocument> arrayFilter = new BsonDocument("element", new BsonDocument("$gte", 100));
    arrayFilters.Add(arrayFilter);

    var updateOptions = new UpdateOptions { ArrayFilters = arrayFilters };
    var result = collection.UpdateMany(filter, update, updateOptions);

Regards,
Wan.

​

[Itzi Kagan]

Thanks Wan,

In that example I have to write the field name ("grades") hard codded in the code.

I was hoping that the driver will do that as it does with all other operations.

Thanks,

Itzhak

[Wan Bachtiar]

In that example I have to write the field name (“grades”) hard codded in the code.

Hi Itzhak,

You can substitute the string grades with a variable.
Are you referring to an unknown field ? Generally you should know which field you’re trying to update.
If not, then I would suggest to reconsider your application data model. See also Data Model Examples and Patterns

I was hoping that the driver will do that as it does with all other operations.

Could you elaborate more with :

• Example documents
• Example code of what you’re trying to do
• Expected outcome after the operation

Regards,
Wan.

​

​

[Itzi Kagan]

Hi, Wan,

What I was hoping for, and still think it should be, is some sort of Builder<T> to to compose the expression, as there is for Filter, Projection, Update etc..

Having a variable means that I have to keep it somewhere in the code. I see it as not a desirable practice, to say the least.

In general, There is so little documentation, if at all, on the 2.5 version of the driver. We are not using any new feature yet, and would very much like to that.

Thanks,

Itzhak

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[jenny lurye]

Hi, Are there any updates on this topic?

I'm also looking for a strongly typed way to work with array filters instead of BsonDocument.

Perhaps there is another way (strongly typed as well) to update a property of an item that is deeply nested inside a sub-sub collection of the documents collection?

For example, if I have a collection of A's of the following structure:

{

     "_Id": "some guid"

      "Bs": [

          {

              "_id":"another guid",

              "Cs":[

                 {

                      "_id": "third id",

                      "property": "I'm the property that needs to be updated",

                 }   

               ]

          }

       ]

}

How can I update the property of C in a typed manner?

Thanks!

Jenny

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[Wan Bachtiar]

Hi Jenny, 

Could you please open a new thread with the following information: 

* MongoDB server version 

* MongoDB .NET/C# driver version 

* Code snippet that you've tried 

Regards, 
Wan.