What is the Danish usage of this? Diary in American English is used for a journal rather than for appointment keeping. NB that for physical objects American English typically uses planner for appointments and a calendar is typically posted on a wall (electronically as in iCal or Google Calendar, it is fine to say calendar).
"Have you your calendar?" is a good sentence, but it is a bit archaic. You can find this word order in Shakespeare and in old songs and nursery rhymes. E.g., the children's rhyme, "Bah bah, black sheep, have you any wool?" for which modern English speakers would normally say, "Do you have any wool?"