Databases

Databases: are permanent (persistent), Related, Organized and Usually stored for a organisation 

External view - what user sees, designed to be helpful for task

Conceptual view - how data is organised

Physical view - how data is actually stored

Flat file - single table, suitable for simple data requirements

Hierarchical - for when data relate to each other like branches on a tree

Serial file - one after the other, stored adjacently

Sequential - data stored in order of important keys values

Exam corrections

For question 2, it was bus topology because there was one linking cable connecting all the devices.

The device was a 

The functions are to share data between workstations, restrict data use for individual accounts