How many lines should each stanza include in an ode?

There doesn't seem to be a fixed length defined for odes. Usually there's three parts: the strophe, anthistrophe and epode, each consisting of at least one stanza, where a stanza is a complete unit in itself. So if you have three lines in each stanza, the only available rhyming scheme would be AAA, because if you do for example ABA, you haven't tied up the B rhyme yet, and the stanza won't be considered closed until you do. You could have four lines in each stanza, opening up more options: ABAB, AABB, ABBA. So the shortest ode would be AAA-BBB-CCC. There are no obvious rules for meter, either.