Entities and relationships

I never really took any effort to bother to know what these are until they got in my way in otherwise fine paper: http://arxiv.org/PS_cache/arxiv/pdf/0710/0710.2083v1.pdf It defines an entity as a relation (aka table:-) with a single noncomposite key, and relationship as a table with composite key. Does this definition pretty much exhausts the entity-relationship theory? Received on Fri Oct 12 2007 - 13:35:15 CDT