This data is highly interconnected. In order to walk though the entire circuit you must query for each component one at a time. Each component will give you the keys needed to query for the next components. Thus, it requires lots and lots of queries to access relatively little data. On the other hand, consider a database of employees.
Lots of data is returned by relatively few queries.
On the other hand, consider a database of employees. Banks use RDBs for maintaining account information. I don't think it is the amount of data but more the interconnectness and the applications' requirements for navigating through the data that distinquishes between OODBs and RDBs. This is an informal message and not an official Mitretek Systems position. If that were the case we would never have projects developed by teams.