$($a$)$ A general practice physician $($GP$)$ serves many patients who subscribe to their own

insurance carrier. Each patient is always served by the same GP and is subscribed

to one insurance carrier. Clearly, many patients may subscribe to the same insurance

carrier. Each insurance carrier has two types of insurance plans. One is for

insurance coverage of outpatient bills with a chosen excess. The other is for

insurance coverage of hospitalization bills in a chosen room type $-$ referred to as

the "room class". The GP needs to keep information about all the treatments that a

patient has received so far. A treatment may include taking multiple drugs. Many

treatments may include the same drug. All the drugs kept in the clinic have been

included in some treatments before.

Draw an entity$-$relationship $($ER$)$ diagram to model the information described.

Please make assumption on the attributes and primary key of each entity type and

include them in the diagram. If you need to make other assumptions, clearly state

them.

$(15$ Marks$)$

$($b$)$ Suppose that a polytechnic university builds a relational database to record

students' industrial attachments $($IA$)$ to organisations. The partial ER diagram is

given in Figure $1$ on page $2$ with primary keys and attributes.