How to open a new database and a new collection in Mongodb

As contrast to relational databases, mongodb doesn't explicitly open a new database or a collection. User just says to mongodb to use a database no matter it is available currently or not. When a save action is performed, this database is automatically created by mongodb. I will take following actions in mongo shell. Currently, I have following databases in mongodb:

 > show dbs
local 0.078125GB
monitoring 0.203125GB
test 0.203125GB

Let me choose another database which is not listed there:

> use sahin_koc
switched to db sahin_koc

Now I am in a new database, but it is temporarily available since there is no record in it. Now let's save a simple record:

> db.test.save({a:1})

When collections is listed, you will see  collection named 'test':

> show collections
system.indexes
test

Save command we have performed also created database named 'sahin_koc'. If we list databases again, we see the name.  Let's also take look at the record saved.

> show dbs
local 0.078125GB
monitoring 0.203125GB
sahin_koc 0.203125GB
test 0.203125GB
> db.test.find()
{ "_id" : ObjectId("52738994698c78841b3f764e"), "a" : 1 }

This tutorial has been done in mongo shell. However, if we want to open database in a code block, we will follow same approach. Database with required name will be opened as it is available. Save action will create it if it doesn't exist. I haven't tested this approach with distinct languages but javascript.