Question

am looking to let the users of my web application define their own attributes for products and then enter data for those products. I have found out that this technique is called n(th) normal form.

The following is DB structure I am currently considering deploying and was wondering what the positives and negatives would be in regards to integrity and scalability (and any other -ity’s you can think of)

EDIT
(Sorry, This is more what I mean)

I have been staring at this for the last 15mins and I know (where the red arrow is) induces duplication and hence you would have to have integrity checks. But I just don’t understand how else what I want could be done.

The products would number no more then 10. The variables would number no more then 200 (max 20 per product). The number of product instances would not exceed 100,000, therefore the maximum size of pVariable_data would not exceed 2 million

Answer 1

Assuming that pVariable is more of a pVariable type, drop the reference to product_fk. It would mean that you need a new entry in that table for every Product record. Maybe try something like this:

Product(id, active, allow_new)

pVariable_type(id, name) 

pVariable_data(id, product_fk, pvariable_fk, non_typed_value, bool, int, etc)

I would use the non_typed_value as your text value, and (unless you are keeping streams) write a record into that field along with the typed value. It will mean keeping the value of a record twice (and more of a pain on updates etc) but it will make querying easier, along with reporting (anything you just need to display the value for).

Note: it would also be idea to pull anything that is common to all products and put them in the product table. For example all products will most likely have a name, suggested price, etc.