ER Databases can not be easily queried

However, in our zeal to make transaction processing efficient, we have lost sight of our original, most important goal. We have created databases that cannot be queried! Even our simple order-taking example creates a database of dozens of tables that are linked together by a bewildering spider web of joins.

.. It is probably accurate to say that this natural dimensional approach was not invented by any single person. It is an irresistible force in the design of databases that will always appear when the designer places understandability and performance as the highest goals.

Conway’s law

organizations which design systems … are constrained to produce designs which are copies of the communication structures of these organizations

.. Although sometimes construed as humorous, Conway’s law was intended as a valid sociological observation. It is based on the reasoning that in order for two separate software modules to interface correctly, the designers and implementers of each module must communicate with each other. Therefore, the interface structure of a software system will reflect the social structure of the organization(s) that produced it.