$1$ a$.$

i$.$ 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.

$-$ Ensure that you document all assumptions that you make about the mapping constraints.

$-$ Ensure that the entities, actions, attributes, and relationships are all shown.

ii$.$ Explain the flistinctions among the terms primary key, candidate key, and super key.

$1$b$.$ For the following relation schema:

employee $($employee$-$name, street, city$)$

works $($employee$-$name, company$-$name, salary$)$

company $($company$-$name, city$)$

manages $($employee$-$name, manager$-$name$)$

Give an expression in SQL for each of the following queries:

i$.$ Find the names, street addresses, and cities of residence for all employees who work for 'First Halal Bank Corporation' and earn more than $\backslash$$$20,000.$

ii$.$ Find the names of all employees in the database who earn more than every employee of 'Barakah Bank Corporation'. Assume that all people work for at most one company.

iii. Find the names of all employees in the database who live in the same cities but on different streets as do their managers.