Error when trying to update MongoDb array element

Question

In my Azure CosmosDb MongoApi I have JSON with an embed array of documents.

{
    \"_id\": ObjectId(\"5a95745df886842904b82f71\"),
    \"token\": \"value1\",         


        

Answer 1

Positional operator is not currently supported by Cosmos DB. Please use the following workaround: iterate over documents and array elements on the client side, change the required element and issue an update on the document with new array:   For example, assuming you have a collection users of following elements:

{ 
    "_id" : ObjectId("59d6b719708b990d6c9b3aca"), 
    "tags" : [
        {
            "id" : 1, 
            "value" : "11"
        }, 
        {
            "id" : 2, 
            "value" : "22"
        }, 
        {
            "id" : 3, 
            "value" : "32"
        }
    ]
}

…you can issue the following command to get one of the elements (with id=1 in this case) updated:  

db.users.find().forEach( 
        function(user) 
        { 
         user.tags.forEach( 
         function(tag) 
         {
               if (tag.id=="1")
               {
                       tag.value = "Updated!";                          
                       db.users.updateOne({_id : user._id}, {$set: {"tags": user.tags}});
               }
        }
        );
       }  
);

You can adjust the condition in if() with even finer granularity than positional operator allows.