Hierarchical

The earliest databases tried to model corporate data on the corporate structures they described. A payroll database would be divided into departments which contained employees who each had names and salaries and particular obligations to maintain. The computer would scan the lists, moving from department to department to find the information it needed. Unfortunately these structures were difficult to search in any order other than the ones initially designed, were extremely difficult to reorganize (in the event the company changed) and required massive duplication of data to make sure information was accessible.