<toc><section id="intro" difficulty="easy"><title>Introduction</title><section><title>Audience</title></section><section><title>Web Data and the Two Cultures</title></section></section><section id="syntax" difficulty="medium"><title>A Syntax For Data</title><section><title>Base Types</title></section><section><title>Representing Relational Databases</title></section><section><title>Representing Object Databases</title></section></section></toc>