A school uses a relational database to manage student enrolment. The entity-relationship diagram below shows part of the database structure. (a) State the t...
Question 1 Report
A school uses a relational database to manage student enrolment. The entity-relationship diagram below shows part of the database structure.
(a) State the type of relationship between STUDENT and ENROLMENT. [1]
(b) State the type of relationship between ENROLMENT and COURSE. [1]
(c) Identify which table acts as the link/junction table. [1]
(d) State two fields, other than key fields, that would be suitable for the STUDENT table. [2]
(e) Explain why the ENROLMENT table is needed rather than directly linking STUDENT and COURSE. [2]
Answer Details
(a) The relationship between STUDENT and ENROLMENT is one-to-many. [1] One student can have many enrolments (i.e. be enrolled on multiple courses).
(b) The relationship between ENROLMENT and COURSE is many-to-one. [1] Many enrolment records can refer to the same course.
(c) The table that acts as the link/junction table is ENROLMENT. [1] It sits between STUDENT and COURSE and resolves what would otherwise be a many-to-many relationship.
(d) Two fields (other than key fields) suitable for the STUDENT table:
- StudentName - stores the full name of the student. [1]
- DateOfBirth - stores the student's date of birth. [1]
Other acceptable fields include Address, Email or TelephoneNumber.
(e) The ENROLMENT table is needed because a direct link between STUDENT and COURSE would create a many-to-many relationship (one student can take many courses, and one course can have many students). [1] A many-to-many relationship cannot be directly implemented in a relational database, so ENROLMENT acts as a link/junction table that resolves it into two one-to-many relationships: STUDENT to ENROLMENT (1:M) and COURSE to ENROLMENT (1:M). [1]
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