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ER diagram and Relational modeling (databases)

Posted on 2001-07-27
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Last Modified: 2008-02-01
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
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Question by:dhinsag
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3 Comments
 
LVL 22

Expert Comment

by:Helena Marková
ID: 6333048
I think that your design is good. There is no need of primary key for Band_Member table.
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LVL 3

Expert Comment

by:ibro
ID: 6335793
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
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Accepted Solution

by:
modder earned 100 total points
ID: 6392515
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.

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