How can I improve this basic ERD of 8 entities?

I am creating an ERD. I have 8 entities so far but I know I've got a long way to go. I think I want to split up orders and purchase orders but not sure in what way. Should I make 3 or 4 entities total out of the orders  and purchaseorders entities?

What else can I do to make this more realistic and correct?
erd.pdf
Mark_CoAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

slightwv (䄆 Netminder) Commented:
I this for a school assignment?

As far as sales orders and purchase orders, I might lean towards a generic order entity then have sales and purchase attributes broken out into their own entity.

So an order can only contain one product?

Then there are things like people and places.  I tend to want to keep them the same.  Maybe a person and address entity with a 'type' flag indicating what entry is what.
0
Mark_CoAuthor Commented:
Yes, I am learning how to make ERDs for my portfolio. So you suggest I turn those 2 entities in to 3: sales, purchases, and orders?
0
slightwv (䄆 Netminder) Commented:
>>So you suggest I turn those 2 entities in to 3: sales, purchases, and orders?

Maybe more.  It depends.

>>I am learning how to make ERDs for my portfolio

How far have you studied thus far?  Are you VERY familiar with the rules of normalization?

http://en.wikipedia.org/wiki/Database_normalization

If you don't have a real good grasp of at least up to 3NF, I would suggest you really dig into it until you understand what it is saying.

The standard saying when normalizing data is:
"The key, the whole key, and nothing but the key, so help me Codd."

Until you understand what that means, it can be pretty hard.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Mark_CoAuthor Commented:
Ok thank you. I appreciate it
0
slightwv (䄆 Netminder) Commented:
Did you really want to close this out this quick?

There are likely other Experts that will have input as well.

If you would like to have this re-opened so they can post, just let me know.  I can take care of that for you.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Oracle Database

From novice to tech pro — start learning today.