What steps will make the definition of a domain in the database?

Question

Database

Question 33 in theory: what steps will make up the definition of a domain in a database?

Answer 1

I dare to suggest that
1) the choice of the base data type,
2) the definition of restrictions.
A domain is a set of valid attribute values. The set of valid values ​​is given by the base type + additional restrictions (CHECK CONSTRAINT), for example, 5 < atr < 50.
By the way, where are the questions from?