Some help with EER Diagrams and Transforming to Relational Tables

[Rick]

Anyone have any experience with these? I'm currently doing an assignment and I'm a bit stuck. The EER diagram has a relationship with a multi-valued attribute and well, I have never been showed an example of what to do in this situation. (This is asking how to transform the relationship with a multivalued attribute to a relational table).

Thanks guiz.

[Toxiic]

Google it.

http://www.tutorialspoint.com/dbms/er_model_to_relational_model.htm

[Rick]

Google it.

http://www.tutorialspoint.com/dbms/er_model_to_relational_model.htm

Thanks for the link, though it doesn't actually have anything mentioning multivalued attributes (double circles). I'll keep trying to google it, though.

[Toxiic]

Thanks for the link, though it doesn't actually have anything mentioning multivalued attributes (double circles). I'll keep trying to google it, though.

ahh . NP. Thought it might be what you were looking for. I know it had a different examples used but seems like that link had nothing to do with multivalued attributes.

[ViciouZ]

Multi valued as in, that a list of "details" instead of just one "details" block? To not violate 3NF, I'd have another table which has just an index and detail column, with multiple entries for each patient-relevantcondition. Dunno though, I don't think that was actually covered in our databases course.

[prozajik]

If you want i could give you some .pdfs from our univeristy, unfortunately they are in czech, but you might be able to get something from that. I could search it for you to find answer you are looking for, but i would need some more explaining to what you exactly want ^^. We had course about it for one whole semester (not only about this, use case diagrams, EER, use case details,...). I passed it, but i dont get it to such and extent that i would be able to help you just by reading your question i am sorry.

Maybe if you got skype or icq or you can contact me on IRC, but you need to tell me when so i go online ^^.


EDIT:
https://mega.co.nz/#!u0ZECYqC!V-idjSijSXPIei7WA4L86DhiztYC5Mpn_GFG8x43XUk

Is page 24 what you are looking for?
Osoba = person
rodneCislo = personal number in your ID card
zaregistrovala = registered
Vozidlo = vehicle (car)
regZnacka = your car number
datRegistrace = date you registered your car

What it actually says is that it depends if you want to save history of registrations or you are fine with just the actual state. The first doesnt save history, the second one does.

[Rick]

Multi valued as in, that a list of "details" instead of just one "details" block? To not violate 3NF, I'd have another table which has just an index and detail column, with multiple entries for each patient-relevantcondition. Dunno though, I don't think that was actually covered in our databases course.

We wern't worried abut normalisation in this assignment, just getting to the final tables using the 8 steps. I ended up making a new table for details and having a composite primary key.

Thanks everyone

Another question:


I thought it meant like, the values in column A of table R that don't have the same B value as the D value in table S. I'm very wrong though, any help is appreciated!

[prozajik]

I don't really know what B<>D is supposed to mean. Do you actually know the answer and just want the explanation or want us to tell you? ^^
That <> is not mentioned in any relational algebra document i found. At first i thought it might be equivalence, but there is no such option. If you have the answer, then my bet would be on (b), but its just a guess.

[Rick]

I don't really know what B<>D is supposed to mean. Do you actually know the answer and just want the explanation or want us to tell you? ^^
That <> is not mentioned in any relational algebra document i found. At first i thought it might be equivalence, but there is no such option. If you have the answer, then my bet would be on (b), but its just a guess.

So '<>' is equivalent to '!=' (not equal to). Yeah, the answer is (a), but I have no idea how it ended up being the answer.

[Cameron]

I don't know much about this but I believe the answer is (c,) but as you obtain a set, all the like terms are only given once, hence you're left with answer being (a)

[Rick]

I don't know much about this but I believe the answer is (c,) but as you obtain a set, all the like terms are only given once, hence you're left with answer being (a)

You're basically right, the only thing is that the projection actually only projects unique values, thus the answer is (a).

[Cameron]

You're basically right, the only thing is that the projection actually only projects unique values, thus the answer is (a).

Yeah, unique would be the better way of putting it haha.