$6\mathrm{.}20$ Construct appropriate relation schemas for each of the E$-$R diagrams in:

a$.$ Exercise $6\mathrm{.}1.$

b$.$ Exercise $6\mathrm{.}2.$

c$.$ Exercise $6\mathrm{.}3.$

d$.$ Exercise $6\mathrm{.}15.$

$6\mathrm{.}1$ Construct an E$-$R diagram for a car insurance company whose customers own one or more cars each. Each car has associated with it zero to any number of recorded accidents. Each insurance

policy covers one or more cars and has one or more premium payments associated with it$.$ Each payment is for a particular period of time, and has an associated due date, and the date when the

payment was received.

$6\mathrm{.}2$ Consider a database that includes the entity sets student, course, and section from the university schema and that additionally records the marks that students receive in different exams

of different sections.

a$.$ Construct an E$-$R diagram that models exams as entities and uses a ternary relationship as part of the design.

b$.$ Construct an alternative E$-$R diagram that uses only a binary relationship between student and section. Make sure that only one relationship exists between a particular student and section pair,

yet you can represent the marks that a student gets in different exams.

$6\mathrm{.}3$ Design an E$-$R diagram for keeping track of the scoring statistics of your favorite sports team. You should store the matches played, the scores in each match, the players in each match, and

individual player scoring statistics for each match. Summary statistics should be modeled as derived attributes with an explanation as to how they are computed.

$6\mathrm{.}15$ Construct an E$-$R diagram for a hospital with a set of patients and a set of medical doctors. Associate with each patient a log of the various tests and examinations conducted.