Consider the ER diagram shown in Figure 3.22 for part of a BANK database. Each bank can have multiple branches, and each branch can have multiple accounts and loans.

a. List the strong (nonweak) entity types in the ER diagram.

b. Is there a weak entity type? If so, give its name, partial key, and identifying relationship.

c. What constraints do the partial key and the identifying relationship of the weak entity type specify in this diagram?

d. List the names of all relationship types, and specify the (min, max) constraint on each participation of an entity type in a relationship type. Justify your choices.

e. List concisely the user requirements that led to this ER schema design.

f. Suppose that every customer must have at least one account but is restricted to at most two loans at a time, and that a bank branch cannot have more than 1,000 loans. How does this show up on the (min, max) constraints?

Figure 3.22

Transcribed Image Text:

BANK BRANCHES BANK_BRANCH Code Name Addr Addr Branch_no АСCTS LOANS N N Acct_no Balance Loan no Amount ACCOUNT Туре LOAN Туре M A_C L_C N. N. Ssn Name Phone CUSTOMER Addr