Of course not all data bases are relational; a very small portion are "object oriented" and a large plurality are probably still hierarchical or networked. However the vast majority of databases for which we construct data models today are relational.

While data modeling and relational database design overlap substantially, their purposes and scope diverge enough to cause users major problems if we ignore their differences. This article examines some ways in which current data modeling tools and methods confuse, mislead, and obscure our database design efforts.