A user-defined method (UDM) is a special kind of UDF that is associated with a user-defined type (UDT).
You write UDMs in the C or C++ programming language, install them in the database, and then use the udt_expression.method_name dot notation to invoke them.
This section uses the term method and the acronym UDM interchangeably. The term type and the acronym UDT are also interchangeable.