In Exercise 6.10 we described companies that have departments, which employ employees. Some employees have had one or more jobs before starting their current employment. The table in Figure 8.9 shows five sample records that represent the employment histories for three members of staff. Each employee is uniquely identified using employee number (eNumber). (Note in this example we do not include the details concerning companies, departments, and dependants.)
(a) The table shown in Figure 8.9 is susceptible to update anomalies. Provide examples of insertion, deletion, and modification anomalies.
(b) Identify the functional dependencies represented by the data shown in the table of Figure 8.9. State any assumptions you make about the data shown in this table.
$$
\begin{array}{|l|l|l|l|l|l|l|}
\hline \text { eNumber } & \text { eName } & \text { DOB } & \text { orgName } & \text { positionHeld } & \text { dateStart } & \text { dateFinish } \\
\hline 0056 & \text { Kate Brown } & 12 / 12 / 76 & \text { Paterson \& Co } & \text { IT Assistant } & 01 / 11 / 90 & 30 / 04 / 95 \\
\hline 0057 & \text { Gillian Bradford } & 01 / 03 / 71 & \text { Willies and Sons } & \text { Technician } & 01 / 06 / 88 & 31 / 03 / 91 \\
\hline 0057 & \text { Gillian Bradford } & 01 / 03 / 71 & \text { Willies and Sons } & \text { Assistant Researcher } & 01 / 04 / 91 & 31 / 03 / 94 \\
\hline 0057 & \text { Gillian Bradford } & 01 / 03 / 71 & \text { Willies and Sons } & \text { Project Manager } & 01 / 04 / 94 & 31 / 01 / 96 \\
\hline 0089 & \text { Stephen Widden } & 09 / 09 / 83 & \text { Paterson \& Co } & \text { IT Assistant } & 01 / 03 / 91 & 31 / 08 / 95 \\
\hline
\end{array}
$$
(c) Describe and illustrate the process of normalizing the table shown in Figure 8.9 to $3 N F$. Identify the primary key and, where appropriate, alternate and foreign keys in each table.
(d) Demonstrate that the functional dependencies identified in part (b) are present in the 3NF tables described in part (c). fig cant copy