Topics include user-defined data types and
     functions.
    </p></li><li class="listitem"><p>
     <a class="xref" href="reference.html" title="Part VI. Reference">Part VI</a> contains reference information about
     SQL commands, client and server programs.  This part supports
     the other parts with structured information sorted by command or
     program.
    </p></li><li class="listitem"><p>
     <a class="xref" href="internals.html" title="Part VII. Internals">Part VII</a> contains assorted