data model problem

[weewizard]

Im a newbie this is my first data model.

I am looking for advice regarding tidying this model up so I can move onto the next stage.

Any comments please give them to me. Greatley Appreciated

Cheers

Richard

[Hartmann]

My only question is can a product be related to multiple product types? According to your model they can't be but is that a possibility? I would build it in just in case.

Also, I would not make the login_name the primary key. Instead, give every user an id. You can keep the login name but use the id as a reference in other tables.

[weewizard]

many thanks for that, ive attatched the up dated version.

question:

My only question is can a product be related to multiple product types? According to your model they can't be but is that a possibility? I would build it in just in case.

Would this create a many to many relationship, if so is not bad practice?

Dose it not mean there should be another table is needed?



Cheers
Richard

[asterix]

Also, I would not make the login_name the primary key. Instead, give every user an id. You can keep the login name but use the id as a reference in other tables.

Why? Where is the value in having multiple users having the same login_name?
You could give login_name a unique constraint and then add an auto_increment, but again why?

It is always best not to introduce new attributes, but to see which of the candidate key has uniqueness and minimality. ergo login_name.

[r937]

asterix, bravo

you saw this other thread, then?

[asterix]

Yep. I love a good multi-post

[madinak]

Hello!
I am new here! I just trying to learn to build data models. Please, share your free resourses with study cases or examples on which I can build my models !
Sincerely yours, Madinak.