Parent technology of meta-languages

Out of interest, here is what I was trying to say/find

SGML is the root parent of html

XML is a cousin to html and nephew of SGML

http://webdesign.about.com/od/sgml/a/how-are-sgml-html-and-xml-related.htm

This one separate a database language into two parts: DDL like create, alter, etc.

And DML as in all the commands: select, update, etc

http://www.tomjewett.com/dbdesign/dbdesign.php?page=ddldml.php