Module $3$

Exercise $3\mathrm{.}18$: Show an alternative design for the attribute described below, that uses only entity types $($including weak entity types, if needed$)$ and relationship types.

$\{$ PreviousEducation $($ CollegeName, StartDate, EndDate,

$\{$ Degree $($DegreeName$,$ Month, Year$)\},$

$\{$ Transcript $($CourseName$,$ Semester, Year, Grade$)\})\}$

Exercise $3\mathrm{.}19$: Consider the ER diagram in Figure $3\mathrm{.}21,$ which shows a simplified schema for an airline reservations system. Extract from the ER diagram the requirements and constraints that produced this schema. Try to be as precise as possible in your requirements and constraints specification.