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2. Attributes

The first thing to working out how entities relate to one another is to be able to define what it is that makes up an entity. If you can't tell apart a dog from a car, it's difficult to say which you should drive to work.

So every entity within a system is given a unique set of attributes that describe them.


An attribute describes one aspect of the entity.

You want the attributes to be as clear as possible, to make it easier to sort data into the correct entities. For example, 'colour' wouldn't necessarily be a good attribute to separate dogs and cars. Both have colours, after all. But only a car will have the attribute 'paint colour', and only the dog would have 'fur colour', so those are better choices for reducing uncertainty about.


In this section, we'll try to be consistent about using just two entities that you might actually find in a database - 'products', and 'suppliers'.

It's time to select some attributes to define these two entities.

Challenge see if you can find out one extra fact on this topic that we haven't already told you

Click on this link: What is an attribute of an entity