Regarding db, collection queries

In our DB list if we don’t have a particular DB called “Sea” but when we say “use Sea” the shell says switched to Sea. Why don’t it give error saying no such DB exists, same is the scenario in using collections while fetching.

use xyz creates an empty DB if it is not there already.
It won’t list
Once you insert documents you can see the new DB

Yes it wont give any error if you try to select from non existing collections or use wrong fields in your query

MongoDB Enterprise Cluster0-shard-0:PRIMARY> show collections
movies
MongoDB Enterprise Cluster0-shard-0:PRIMARY> db.movies.find({“ABC”:“nothing”})
MongoDB Enterprise Cluster0-shard-0:PRIMARY>