
Originally Posted by
it-ogo
There are terminological contradictions among the linguists. Some define case through the grammatical function, others - through the morphology. If you like (or found in internet first) morphological approach, it does not mean that others are impossible. Don't confuse the way of description with the law of nature and formalism with the essence. If you don't like term "Partitive case" you can use "Partitive function of Genitive case". Which sometimes can have alternative morphological form (case) unlike other functions.
So, if the question was: does "Хочешь воды?" mean "Do you want some water?" than answer is simple "Yes". Independently of any smart system of cute words you prefer to describe that phenomenon.