Delia supports inheritance for both scalar and struct types.
A custom scalar type is a scalar type that you define:
type Temperature int end
It is used in conjuction with validation rules and will be covered there. (See …)
A struct type can inherit from another struct type. The derived type has all the fields of its base type(s).
 type User {
   id int primaryKey
   username String
   password String
 }
 type Customer User {
   lastPurchaseDate date
   shoeSize number
 }
The Customer type will have five fields: id, username, password, lastPurchaseDate, and shoeSize.