Now learn the dative case. Suppose I say to you "Give me your book." The word 'me' is in the dative case, because what I really mean is "give TO me". The dative case is any time you say or imply to, for, by, from, and so on.
"To whom is this letter addressed?""
But this is not dative:
"Who is the boss here?"
(Because what you mean is "I am the boss.")