Thank you for quick answers for Hornbydd and rborchert. But I have some additional question. As i I understand, I can add only one sub-type for shape in geotabase. As an example. I have a list of countries sorted by continent and a list of cities for each country.
Continent Country City
america USA NY
Miami
Seatle
Canada Toronto
Ottawa
europe UK London
Manchester
France Paris
Lille
I create sub-type for field 'Continent', so user can choose continent. Then I create domains for field 'Country'. In this example there will be two domains: for countries in america and for countries in europe. Then I need to create domain for field 'City'. I create one domain, which will contain all cities in USA and Canada. So the question: is it possible when I choose in field 'country' USA in field 'City' I will see cities only in USA, but not all cities in USA and Canada. The main idea, that the value of field 'city' will depend on value in field 'country'.
Maybe it's too long and complex explanation of my case) and sorry for grammar mistakes (it's not my native language)