Ashley P.

asked • 04/09/20

ER Diagrams - relations

The SingLanka Record Bar has decided to store information about musicians who perform on its albums in a database. Consider the following requirements to design a database for the company (SingLanka Record Bar).

 Each musician that records at the company has a NIC, a name, date of birth and phone number. Each musician is identified by a NIC. However, musician may have several phone numbers.

 Each instrument used in songs recorded at the company has a unique identification number, a name (e.g., guitar, flute, drum) and a musical key (CD or MC), and an album identifier.

 Each song recorded at the company has a title (unique) and an author.

 Each musician may play several instruments, and a given instrument may be played by several musicians.

 Each album has a number of songs on it, but no song may appear on more than one album.

 Each song is performed by one or more musicians, and a musician may perform a number of songs.

 Each album has exactly one musician who acts as its producer. A musician may produce several albums.

a) Draw an ER diagram that captures the above requirements by indicating relevant attributes along with the primary keys. Also specify cardinality and participation constraints. State any assumptions you have made.

Is there any type of relation between musician and phone number here?

Is phone number a weak entity type of musician??

1 Expert Answer


Vinayak P. answered • 04/11/20

5 (6)

Senior Software Engineer

Ashley P.

Is that fine even if we take phone no as a multi-values attribute?


Vinayak P.

Yes. Each person may have many phone numbers. But multiple phone numbers will only be added with at least one musician in the musician schema.


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