So, is "bread knife" a commonly-used phrase in Russian (with bread being an adjective of sorts), or do they think of it as "a knife for bread," as stated? If we can use "bread knife", what would the cases then be?
it is accepted when you translate to english, when speaking russian you should just stick with the original phrase)
Ah, I was confused with для and genitive negation. Because it is для that makes хлеб genitive, if this is an affirmative sentence ножа becomes нож while хлеб keeps хлеба, right?
But why? I would think this calls for dative, as the bread is an indirect object - "for the bread".
So, each preposition requires a specific case for the noun it modifies, regardless of that noun's position or use in the sentence - ? If so I could understand this as German has similar rules.
Basically yes, and the preposition is almost always going to precede the noun it modifies, with the exception of certain idiomatic expressions.
Declined :). Yes, «для» is used with the Genitive, same as an impessive number of other prepositions.
You never say "есть" if you don't have something. You replace it with "нет" and change the word to genitive. У меня есть нож - У меня нет ножа.