How can I delete nested array element in a mongodb document with the c# driver

Question

I am new in the MongoDB world and now I am struggling of how can I delete, update element in a nested array field of a document. Here is my sample document:

{
    "_id" : ObjectId("55f354533dd61e5004ca5208"),
    "Name" : "Hand made products for real!",
    "Description" : "Products all made by hand",
    "Products" : [ 
        {
            "Identifier" : "170220151653",
            "Price" : 20.5,
            "Name" : "Leather bracelet",
            "Description" : "The bracelet was made by hand",
            "ImageUrl" : "https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQii6JCvXtx0iJGWgpvSl-KrdZONKYzDwS0U8uDvUunjO6BO9Aj"
        }
    ]
}

In my method, I get the id of the document and the id(Identifier) of the Product that I want to delete. Can anyone tell me how can I delete from the Products field the element having Identifier: 170220151653?

I tried:

var query = Query.And(Query.EQ("_id", categoryId), Query.EQ("Products.Identifier", productId));
var update = Update.Pull("Products", new BsonDocument() { { "Identifier", productId } });
myDb.Applications().Update(query, update);

as suggested here: MongoDB remove a subdocument document from a subdocument

But I get an error at

myDb.Applications()

It just can't be found.

SOLVED:

var pull = Update<Category>.Pull(x => x.Products, builder => builder.EQ(q => q.Identifier, productId));
collection.Update(Query.And(Query.EQ("_id", ObjectId.Parse(categoryId)), Query.EQ("Products.Identifier", productId)), pull);

you want to delete only Identifier or whole array ?

Neo-coder
– Neo-coder

2015-02-18 13:51:16 +00:00
Commented Feb 18, 2015 at 13:51 — Neo-coder
– Neo-coder, Commented Feb 18, 2015 at 13:51
@yogesh the whole element that has that Identifier

mathinvalidnik
– mathinvalidnik

2015-02-18 13:52:47 +00:00
Commented Feb 18, 2015 at 13:52 — mathinvalidnik
– mathinvalidnik, Commented Feb 18, 2015 at 13:52
stackoverflow.com/questions/34115181/…

CodeMan
– CodeMan

2015-12-08 06:29:25 +00:00
Commented Dec 8, 2015 at 6:29 — CodeMan
– CodeMan, Commented Dec 8, 2015 at 6:29

neleus · Accepted Answer · 2015-02-18 14:56:31Z

15

You are calling method Pull(string name, MongoDB.Bson.BsonValue value) and according to the docs it

Removes all values from the named array element that are equal to some value (see $pull)

and you provide { "Identifier", productId } as the value. I guess that mongo does not find that exact value.

Try to use the second overload of Pull with query-condition instead of exact value

Removes all values from the named array element that match some query (see $pull).

var update = Update.Pull("Products", Query.EQ("Identifier", productId));

UPDATE

Since you mention Category entity so I can suggest using lambda instead of Query.EQ:

var pull = Update<Category>.Pull(x => x.Products, builder =>
builder.Where(q => q.Identifier == productId));

edited Feb 18, 2015 at 14:56

answered Feb 18, 2015 at 14:20

neleus

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1 Comment

neleus Over a year ago

Update<Category> hmmm, you didn't mention that you have Category type... Anyway this is the strongly-typed case of my solution, please dont forget to mark the answer.

fatihyildizhan · Accepted Answer · 2020-08-08 10:51:34Z

10

Solution with C# MongoDB Driver. Delete a single nested element.

var filter = Builders<YourModel>.Filter.Where(ym => ym.Id == ymId);
var update = Builders<YourModel>.Update.PullFilter(ym => ym.NestedItems, Builders<NestedModel>.Filter.Where(nm => nm.Id == nestedItemId));
_repository.Update(filter, update);

answered Aug 8, 2020 at 10:51

fatihyildizhan

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1 Comment

user10706046 Over a year ago

Is using the Builder in the 2nd argument of PullFilter necessary? A lambda automatically infers the NestedModel type, so it'd be nm => nm.Id == nestedItemId instead of Builders<NestedModel>.Filter ...

fatihyildizhan · Accepted Answer · 2020-08-08 10:52:15Z

4

I had the same of deleting elements from the nested array but after research, I found this piece of working code.

var update = Builders<Category>.Update.PullFilter(y => y.Products, builder => builder.Identifier== productId);
var result = await _context.Category.UpdateOneAsync(filter, update);
return result.IsAcknowledged && result.ModifiedCount > 0;

edited Aug 8, 2020 at 10:52

fatihyildizhan

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answered Feb 8, 2020 at 5:53

Deepak

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Comments

Binod Mahto · Accepted Answer · 2015-08-21 11:56:44Z

3

I was also facing the same problem and then finally after doing lot of R&D, I came to know that, you have to use PullFilter instead of Pull when you want to delete using filter.

answered Aug 21, 2015 at 11:56

Binod Mahto

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fatihyildizhan · Accepted Answer · 2019-12-05 11:15:38Z

0

Hi as per my understanding you want to remove whole matched elements of given id and identifier so below query will solve your problem but I don't know how to convert this into C#, here mongo $pull method used.

db.collectionName.update({"_id" : ObjectId("55f354533dd61e5004ca5208")}, {"$pull":{"Products":{"Identifier":"170220151653"}}})

edited Dec 5, 2019 at 11:15

fatihyildizhan

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answered Feb 18, 2015 at 14:03

Neo-coder

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1 Comment

mathinvalidnik Over a year ago

Yes. I checked this one. It just doesnt work for me. I need it as C# Driver code. But thanks :)

fatihyildizhan · Accepted Answer · 2019-12-05 11:20:37Z

0

Solution for C# MongoDB Driver. You can set empty [] the nested array.

var filter = Builders<MyUser>.Filter.Where(mu => mu.Id == "my user id");
var update = Builders<MyUser>.Update.Set(mu => mu.Phones, new List<Phone>());
_repository.Update(filter, update);

answered Dec 5, 2019 at 11:20

fatihyildizhan

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