Obsessed with Oracle PL/SQL

In my first post on object-oriented programming in PL/SQL, I introduced the object type (our version of a class) and showed how you needed to instantiate an object type instance before you could work with it. In this post, I explore how to create a hierarchy of types. Type or class hierarchies are a key concept in object-oriented programming, because of the way that subtypes inherit attributes and methods from their parent types. All the code you see below can be run in Oracle LiveSQL through this script . Let's revisit the root type of my hierarchy: food. CREATE TYPE food_ot AS OBJECT ( name VARCHAR2(100), food_group VARCHAR2 (50), grown_in VARCHAR2 (100) ) NOT FINAL ; A very simple type: it contains just three attributes and no methods (procedures or functions). It also contains the NOT FINAL clause. This means, rather obviously, that I am "not done." What that means in the context of object types is that I might want to create a ...