Frequently Asked Questions
about data modeling
Q: How much information (how many entities, attributes...) should I model?
You need to model everything that is explicitly mentioned in the text of the exercise. You can add a little more, just to make the
exercise more realistic. Make sure that every entity has at least a couple of attributes. Do not overdo. Ask the Prof. if in
doubt.
Q: Should I have an "invoice" entity?
No. ACME and UBC are moving towards a "pay-upon-receipt" invoiceless system.
Q: Can I assume that there is only one item (product) per order?
No.
Q: Can I assume that there is only one vendor (i.e., UBC) or only one client?
No.
Q: If some data is external to my company, do I need to model it?
Yes, but only what you are using internally.
Q: What is a packing list?
A packing list is a document that travels with the goods being shipped. It tells the truck driver what to deliver and where to
deliver it, and it tells the receiving dock worker what is being delivered.
Q: Last minute advice?
Do not forget to write your name and the name of the function that you are modeling (e.g., 'shipping'). If things get
frustrating, relax. Step away from the ERD for a bit. Avoid analysis paralysis. Seek faculty help.