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.