Re: Entity and Relationship - the same thing ?
Date: Sun, 5 May 2002 16:40:02 +0200
On Sat, 4 May 2002, Sleeves wrote:
> [...] For instance, having explained entities and it's attributes
> (example entity "customer" with its attributes being "name" "age"
> etc), we now go onto relations and its attributes, where the relation
> has its primary/foreign keys defined using the attributes etc, but am
> I right in saying they are exactly the same thing or am I getting
> myself totally confused here ?
The basic idea is that entities represent things that you want to say something about, and that relationships represent facts you want to say about them. This is not really a clear-cut distinction because sometimes facts are also things that you want to say something about, so some relations can also be seen as entities. Whether this is actually allowed in the modelling technique that your course is using, may depend upon the specific technique (some allow it, some don't). So your confusion is justified. :-)
- Jan Hidders