>> In addition, IDS and other network systems encoded what we now think of as the “joins” between different kinds of records as part of the database structure r

>> In addition, IDS and other network systems encoded what we now think of as the “joins” between different kinds of records as part of the database structure rather than specifying them in each query. -- This is basically Neo4j and other graph databases. See: http://maxdemarzidotcom.files.wordpress.com/2012/08/screen-shot-2012-08-13-at-7-40-20-pm.png http://maxdemarzidotcom.files.wordpress.com/2012/08/screen-s... Those "R1", "R2"s in the picture... those are your "joins".