Oracle PL/SQL Tutorial/PL SQL Data Types/Subtype Custom Type

Defining Your Own Datatypes

You can create PL/SQL datatypes in the declaration portions of procedures, functions, root anonymous blocks, package bodies, and package specs.

You create SQL types by using a DDL operation with the following syntax:

   <source lang="sql">

type newType is definitionOfTheType;</source>

Keeping Code Consistent with User-Defined Subtypes

   <source lang="sql">

declare

 subtype newSubtype is standardType [NOT NULL];</source>