• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 663
  • Last Modified:

ER diagram and Relational modeling (databases)

I have designed a ER-diagram/normalisation.
However I am not very Confident, that I have got all the entities and attributes.
Could you please suggest the entites and attributes needed for me to design the ER-diagram correctly
please.
Once I have the correct diagrams I will implement the database on oracle.
#################################################
The domain is the following:
I am to design a MUSIC database which is a database about bands and musicians. A musician can belong
to several bands. Information is maintained on each musician, such as name, address, phone number and
instruments played (information kept for instruments themselves includes name and type). For each band,
there is exactly one "contact person", who need not be a member of the band. The same information that
is kept for musicians is maintained for contact persons. Assume that the name of any musician or contact
person is unique in the database. Each band has a name (which need not be unique and can change over
time). In addition, each musician plays one or more instruments at a proficiency level which can be
novice, intermediate, expert or professional.

Feel free to make additional assumptions about the real world in the design.
#################################################

could you Please Please confirm the following:

Q1) Are these the correct relationships between the entites please;
PROFICIENCY - 1:1 - PERSON
BAND - M:N - PERSON
PERSON - M:N - INSTRUMENT
INSTRUMENT - M:N - BAND_MEMBER
BAND_MEMBER - 1:N - BAND


Also are the attributes that I have put 'stars' around correct primary keys please, however I could
not establish which attributes was the primary key for
Band_Memebr;
#######################################################################
Instrument
**instrument_id**
instrument_name
instrument_type

Proficiency
person_id
instrument_id
**persons_proficiency**

Person
**person_id**
person_name
person_address
person_phone

Band_Member
band_id
person_id

Band
**band_id**
band_name
band_contact_person_id

##########################################################

PS. I tried to insert a diagram of the ER that I produced but had no luck, sorry.Any advice would be
very much Appreciated.

Thanks.

Kind regards,
GD
0
dhinsag
Asked:
dhinsag
1 Solution
 
Helena Markováprogrammer-analystCommented:
I think that your design is good. There is no need of primary key for Band_Member table.
0
 
ibroCommented:
I will suggest you to MotherBankKey in the Band table. It will contain an optional "mother" band id. This will be in case that band splits or changes it names. Also put a status flag in Band: say "1" is active, "0" former, "2" retired, etc.
 hope this helps
0
 
modderCommented:
Everybody, this is a homework question, and in case you are in doubt, asker has confirmed this in e-mail conversation.

Experts-Exchange is *not* a homework service. In actual fact, our member agreement specifically states that doing someone else's homework for them is not allowed.

Member agreement:
http://www.experts-exchange.com/jsp/infoMemberAgreement.jsp

Section 3, in which it states that EE is not to be used for:
* violating the guidelines for academic honesty or other unethical behavior.

It is OK to help people when they run into specific problems when they're doing their homework. But in this case asker simply gives you the problem they've been given to solve. That will not be accepted.

The question has been force-accepted to moderator account so that nobody can benefit from answering this question. You will *not* benefit from doing someone's homework for them.

And dhinsag, do not let me see you post another homework question. Doing so will result in termination of your account.

Regards
modder@experts-exchange.com
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Tackle projects and never again get stuck behind a technical roadblock.
Join Now