CREATE DOMAIN PERSON CLASS { ssn ASSELECT SSN FROM Person WHERE Object = THIS firstName ASSELECT First_Name FROM Person WHERE Object = THIS parents ASSELECT Parent FROM Parenthood WHERE Child = THIS children ASSELECT Child FROM Parenthood WHERE Parent = THIS }
方法:
CREATE DOMAIN PERSON CLASS { setName(newName : String) ASUPDATEWHERE Object = THIS }
继承:
CREATE DOMAIN PERSON CLASS {} CREATE DOMAIN EMPLOYEE CLASS EXTENDS PERSON {}