How do I define my own datatype in Base?

In most SQL implimentations, you can define your own datatypes using CREATE DISTINCT. I can’t seem to make this work in Base. Is it possible to do?

I believe you are referring to CREATE TYPE which is not available in the HSQLDB v1.8 which comes with LO. It is available in later versions (2.3.x) which can be used in split or server modes.