This page is part of the book SQL-99 Complete, Really, by Peter Gulutzan & Trudy Pelzer. The authors have graciously allowed us to reproduce the contents of the book here. Because the book is about the SQL-99 standard, the contents of this and other pages in the book may not directly apply to MariaDB. Use the navigation bar to navigate the book.

[Obscure Rule] applies for this entire chapter.

In SQL, a <reference type> is a pointer: a scalar constructed SQL <data type>. It points to a row of a Base table that has the with REF value property that is, a <reference type> points to a UDT value. Unless you are familiar with Object-Oriented Programming, this chapter will probably not be fully comprehensible until you have read Chapter 27 "User-Defined Types".