Updating embedded documents mongodb

In that case arr: would match the first element (the element has a field "a" with value 1) bit arr: would not (the element is and not .

The query part must uniquely identify an array element for the positional operator and is not semantically equivalent to the $elem Match version.First, increment any document that has "items.item_name" equal to "my_item_two".For this you'll have to use the positional "$" operator. We can push a new item to an array without a "my_item_two" as follows: For your question #2, the answer is easier.The risk is that some other process could modify the array in the meantime, so you would overwrite its changes.To avoid this, you can use optimistic locking, especially if the array is not modified every second.

Leave a Reply