I tried the following code in mongo-shell, but it seems contradiction :

> db.doc.drop()
> db.doc.save({ versions :

{ '1.1' : 0 }

})
Sat Oct 30 19:00:39 uncaught exception: can't have . in field names [1.1]

> db.doc.save({})
> doc = db.doc.findOne()
> db.doc.update({_id : doc['_id'] }, { versions :

{ '1.1' : 0 }

} )
> db.doc.findOne()
{
"_id" : ObjectId("4ccbfb31fe8d276c4eb1b846"),
"versions" :

{ "1.1" : 0 }

}

If mongo does not allow field names that have dot, then I should not allow to save in any way.