Grammatical Cases
Grammatical cases are applied to nouns and pronouns to indicate what role they play in a sentence.
(i.e. Object, Subject, Possessor)
e.g. In the sentence "Mary fed cake to the dog", Mary is the subject, Cake is the direct object, The Dog is the indirect object (the thing that something is being done to).
Accusative Case
The accusative case of a noun is used to mark the object of a sentence.
e.g. In the sentence "Bob read the book", The Book is the object, and hence has the accusative case applied to it.
Dative Case
The dative case is applied to the object in a sentence that an action is being applied to.
e.g. In the sentence "Heidi gave the ball to Sally", Sally is the indirect object, and hence has the dative applied to her.
Nominative Case
The nominative case is applied to the subject of a sentence.
e.g. In the sentence "Sarah went swimming", Sarah is the subject and hence has the nominative case applied to her.