Your hand drawn $($pencil$/$paper$)$ ENHANCED CHEN METHODOLOGY $($Ovals for

attributes, Diamonds for Relationships$).$ Take a picture of your drawing $($EER Data Model$)$ and

post it to Canvas in the Assignment #$2$ section

$3-25$

For a library, the entity type HOLDING has four sub$-$types: BOOK, AUDIO BOOK, DVD$,$ and

SOFTWARE. Draw a separate EER diagram segment for each of the following situations:

a$.$ At a given time, a holding must be exactly one of these subtypes.

b$.$ A holding may or may not be one of these subtypes. However, a holding that is one of

these subtypes cannot at the same time be one of the other subtypes.

c$.$ A holding may or may not be one of these subtypes. On the other hand, a holding may

be any two $($or even four$)$ of these subtypes at the same time.

d$.$ At a given time, a holding must be at least one of these subtypes.

$3-26$

A bank has three types of accounts: checking, savings, and loan. Following are the attributes for

each type of account:

CHECKING: Acct No$,$ Date Opened, Balance, Service Charge

SAVINGS: Acct No$,$ Date Opened, Balance, Interest Rate

LOAN: Acct No$,$ Date Opened, Balance, Interest Rate, Payment

Assume that each bank account must be a member of exactly one of these subtypes. Using

generalization, develop an EER model segment to represent this situation using the traditional

EER notation, the Visio notation, or the subtypes inside supertypes notation, as specified by

your instructor. Remember to include a subtype discriminator.