CENTRAL SCHOOL LIBRARY
Observe the ER diagram for the CENTRAL SCHOOL LIBRARY

-How many columns will the relation COPY have in the relational schema mapped from the Central School Library ER diagram?
A)2
B)3
C)4

Question

CENTRAL SCHOOL LIBRARY
Observe the ER diagram for the CENTRAL SCHOOL LIBRARY
 
-How many columns will the relation COPY have in the relational schema mapped from the Central School Library ER diagram?
A)2 
B)3 
C)4

Quizplus · Accepted Answer

The COPY relation has three columns: copy_id, accession_number, and book_id. The copy_id attribute uniquely identifies each copy of a book, while the accession_number attribute uniquely identifies each physical item of the book (i.e. each physical book in the library). The book_id attribute links the COPY relation to the BOOK relation, indicating which book the copy belongs to.

CENTRAL SCHOOL LIBRARY Observe the ER Diagram for the CENTRAL SCHOOL LIBRARY