The following THREE (3) tables are a small part of the relational database at Not-Quite-Right University.The attributes assigned to each table are contained inside the brackets. Currently the university has a policy that students cannot repeat a unit.(Note: 'Unit' refers to a single semester length subject.Each unit has a staff member who acts as chief examiner responsible for that unit.)

STUDENT-UNIT-RESULT (StudNum, UnitID, Grade)

STUDENT (StudNum, StudName, StudAddr, PhNum, DegreeCode, DegreeName)

UNIT (UnitID, UnitName, StaffID, StaffName, StaffOffice)

Required:

(a)Using an example from ONE (1) of these tables, explain in precise terms the concept of "functional dependence", including the direction of any dependence.

(b)What purpose does a 'primary key' serve in a relational database table?

(c)Given the current structure of the STUDENT-UNIT-RESULT table, why would the 'StudNum' attribute not be a good primary key for this table?What would you recommend, instead?

Question 2 (cont'd)

(d)In respect of the current data structure given in these tables, and assuming you were able to identify the most appropriate primary key for the STUDENT-UNIT-RESULT table, not all of the tables are at third normal form (3NF).This can lead to anomalies in respect of: "1. Insertion; 2. Update; or 3. Deletion" of data in these tables.Briefly explain TWO (2) of these types of anomalies using examples related to the current data structure (i.e. from data that would be stored in these tables).

(e)The three tables given at the start of this question are reproduced below (to make it easier for you to complete this part of the question).

STUDENT-UNIT-RESULT (StudNum, UnitID, Grade)

STUDENT (StudNum, StudName, StudAddr, PhNum, DegreeCode, DegreeName)

UNIT (UnitID, UnitName, StaffID, StaffName, StaffOffice)

Normalising, to third normal form (3NF), these three tables will result in a data structure that consists of five tables.Using the same style of notation in your answer (i.e. with the table name given and then the attributes for that table listed within a set of brackets), list below these five tables.Underline and bold one or more of the attributes of each table to indicate the primary key of that table (so the primary key of each table clearly stands out in your Word document).