Has E/R had a negative impact on db?

I don't like entities. In fact I despise entities, as the enemy of good information philosophy. You see I just don't accept their existence. There is no magical wrapper surrounding some construct that turns it into a nicely formed 'thing' or 'object'. Sure, we can invent them, but there is never any inherent truth to their boundaries. Now in the constraints of a piece of my OO code, which is only going to be used by other parts of my code, and whose domain I have total control over this is not a problem. But everywhere else in information modelling it is, as it encourages one to view those boundaries as non-decomposable.

To me the situation get worse when one then adds relationships between entities. What on earth is the difference between an entity (an association of attributes) and a relationship (an association of entities), except for the fact that a relationship is constrained to being binary. Nothing. In fact all they are, are special cases of n-ary relationships, or 'associative entities'. Everything we want to model is ultimately an associative entity, or better put everything we want to model is an n-ary _relationship_.

Now Codd grokked this. I am sure he did. That's why the RM has no 'links' and pivots on the information principle. Chen did not - remember his E/R model was originally intended to be a direct competitor to RM, not just a tool for conceptual modeling.

Okay, so for those in the know this isn't an issue and E/R is a useful tool. But for those not in the know (which appears to be a lot of the industry) it promotes the fallacy of the Entity/Relationship distinction, of impenetrable wrappers, and encourages the mindset that has lead to OODBMS, XML databases, etc.

So I put to you that Chen's E/R has had a greater deleterious influence to fashion in db theory than any other paper in the last 30 years. Received on Thu Apr 20 2006 - 15:54:46 CEST