How can I update mongodb document for adding a new item to array?

Question

I couldn't figure out insert to a sub array...

_id
MyArray
--Item
----ArrayItemId
----Name

I want to insert items to MyArray...

How my update document should be?

MyCollection.Update( 
 new QueryDocument { { "_id", MyObject.Id } },
 new UpdateDocument { { "$set", new BsonDocument { { "MyArray", 
       new BsonArray { new BsonDocument {{ "ArrayItemId", myArrayField.Id }},
                       new BsonDocument {{ "Name", myArrayField.Name }} }}}}}, 
 UpdateFlags.None);

score 30 · Answer 1 · answered Dec 26 '15 at 09:29

30

Syntax for new MongoDB c# async adapter:

var filter = Builders<myObject>
             .Filter.Eq(e => e.Name, "name");

var update = Builders<myObject>.Update
        .Push<String>(e => e.MyArray, myArrayField);

await collection.FindOneAndUpdateAsync(filter, update);

answered Dec 26 '15 at 09:29

Ofir

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what should i write behalf of string – Chitra Nandpal Jul 31 '18 at 12:55
1

you can skip the "String" in Push as it can be inferred from the specified datatype in update field (e.MyArray) – Sunny Sharma Feb 15 '19 at 07:21

score 19 · Accepted Answer · answered Dec 02 '11 at 10:35

19

Inserting in an array is done using the $push operator.

As a side note, you don't need to use QueryDocument and UpdateDocument. There's a much easier helper syntax:

MyCollection.Update(Query.EQ("_id", MyObject.Id), 
                    Update.PushWrapped("MyArray", myArrayField)

Note that PushWrapped<T> allows to push documents, while Push accepts only such types that can be represented by a simple field in MongoDB.

answered Dec 02 '11 at 10:35

mnemosyn

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thanks. But for Update.PushWrapped what should I reference... Intellicense is not seeing it... – Serdar Dec 02 '11 at 10:45
4

I think it is now ... new UpdateBuilder().PushWrapped in the new version – Serdar Dec 02 '11 at 11:00

How can I update mongodb document for adding a new item to array?

2 Answers2