The table below lists customer/car hire data. Each customer may hire cars from various outlets throughout Glasgow. A car is registered at a particular outlet and can be hired out to a customer on a given date.

Question


(a) The data in the table is susceptible to update anomalies. Provide examples of how insertion, deletion, and modification anomalies could occur on this table.
(b) Identify the functional dependencies represented by the data shown in the table. State any assumptions you make about the data.
(c) Using the functional dependencies identified in part (b), describe and illustrate the process of normalization by converting Table 1 to Third Normal Form (3NF) relations. Identify the primary and foreign keys in your 3NF relations.

Answer 1

(a) Using the data shown in the table above, the student should provide examples of how insertion, deletion, and update anomalies could occur.
(b) For answer see figure below.
Students should identify that jobId is the PK for the table and then show the three functional dependencies. Students may split up the pickupDateTime column to separate Date and Time…This is OK but not necessary. The original table is in 2NF and is transformed into 3NF by removing functional dependencies fd2 and fd3. The structure of the three tables created is shown below.