The Dative case is chiefly used to indicate the person for whom (that is, for whose advantage or disadvantage) an action happens or a quality exists. In a sense, all datives are Datives of Reference or Datives of Advantage and Disadvantage; as a result that particular category is not very useful though it does remind that the Dative case refers to a personal or affective interest in the action. The most useful and common translation of the dative case into English is with the preposition "for". Our sense that the dative is to be translated with the preposition "to" is a result of the common use of the dative with a verb of giving where the English idiom is "I give this to you." However, even with the indirect object you can see how "for" is the basic sense if you imagine someone handing you a book and saying "For you." Handy tip: If a word does not have a preposition and could be either a dative or an ablative, it is a dative if it is a person, an ablative if it is a thing. Exception: the Ablative Absolute. The following categories are the most common and useful.
Dative with Intransitives: Intransitive verbs of affect and personal relationship, often in the second conjugation (eg. noceo, faveo, voveo, caveo, studeo, pareo), take the dative of the person affected by the action or emotion.
Dative with Compounds: Verbs, especially the verb "to be", when compounded with a pre-verb (a preposition used adverbially and attached directly to the root verb) take a dative whose meaning goes very closely with the new sense imparted to thecompound verb by the pre-verb. For example: desum = "to fail", desum tibi = "to fail you"; praesum = "to protect, to stand over", praesum vobis = "to protect you, to stand over you"
When the verb was a compound of a separative pre-verb (ad, de, ex) and the stem, the dative was used when the sense in English suggested an ablative. For this reason, a special category of the dative with compounds is the dative of separation: absum tibi = I am absent from you; extorta tibi = ripped from you.
Dative with Impersonals: Impersonal verbs like licet, libet, placet, expedit, accidit, contingit take the dative of the person.
Dative of Possession: The dative is used with the verb "to be" to indicate the person for whose benefit something exists. In many cases, this implies possession. The Dative, however, is different from the Genitive of possession in that it typically implies a personal connection of use, enjoyment, etc. that goes beyond the legal possession. For this reason, sometimes this dative is called the "sympathetic dative".
Dative of the Person Judging: Someone's "interest in a thing or quality" may be specifically that of judgment or perspective. When this is the case, the Dative is used. Some examples may help to clarify the range of this dative. Qualities: tu mihi es carus = "you are dear to me", that is, "for me, in my eyes, you are dear". Judgment: inimicus mihi videtur = "he seems to me to be an enemy", that is, "in my judgment, from my perspective, he appears in a certain light.
[NOTE: this sentence could also mean that "he seems to be an enemy to me"]. Perspective: Roma venientibus hoc oppidum primum est. = "this is the first time for those coming from Rome" or "As you come from Rome, this is the first town."
Dative of the Agent: The Dative is used with the Gerundive to indicate the person upon whom the obligation or necessity lies. Since this readily implies that that person will have to do something, this Dative is called the Dative of Agent, although it is not strictly speaking a agent. Consider: agenda = things to be done. haec tibi agenda sunt = "these things are to be done by you" OR "these are the things for you to do" OR "for you this is the agenda." See additional Dative of the Agent examples.
Ethical Dative: The weakest form of the Dative is the Ethical Dative. Here, the dative pronoun indicates the person who has a general interest in the activity, and when that person is talking to another, "for me" becomes the equivalent of "please". The usage is colloquial and is confined to certain kinds of situations. Thus, the first person usually means "please", as above; the second person is used to draw one's interlocutor attention and is translated with phrases like "lo" and "for your pleasure." This form is not found in English, although it used to be possible -- an ethical dative which is misunderstood by the servant at the beginning of Romeo and Juliet makes for a piece of slapstick: "Come, knock me at that door." -- so the slave does.
Predicative Dative or Dative of Purpose and Result: The Dative, as the usages above indicate, is usually a person or a personal noun. The most significant exception to this rule is the Dative of Purpose, also called the Dative of Service or Purpose, the Dative of Purpose and Result and the Predicative Dative. It is used with abstract verbal nouns, usually from the language of crafts, including warcraft, to indicate the end that is effected by the verb. receptui canere = "to sound [the signal] for retreat". Other common idioms: auxilio mittere = 'to send [someone] to be a help"; puella mihi est curae = "the girl is a concern to me"; usui esse = to be for use; quaestui habere = to have as a source of profit; locum castris deligere = to select a place for the camp.