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2. Attributes

The first step to describing the relationship between entities is to be able to define the entities.

So every entity within a system is given a unique set of attributes that describe them, and only 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 way of distinguishing dogs from cars, since both dogs and cars have a colour. A better choice of distinguishing attributes would be 'paint colour' for cars, and 'fur colour' for dogs.


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