underlying technologies of opacs?

[rob caSSon]

stumbled across this, altho their categorizations seem simplfied....

	http://www.biblio-tech.com/html/product_dbms.cfm

looks to me like they are referring to multivalue systems as "Nested
RDBMS"....other than than, looks like a good summary.....

on a related note, i've heard that a lot of these products that employ an
RDBMS don't actually map MARC to a database structure, but simply store
the record as a whole; this is simply grapevine information...anyone more
qualified to speak to this?

and thanks to everyone contributing to this thread.....it's been
informative; i'm an ohio boy, who has only dealt with III ;)
rob