Consider the two tables 71 and 72 shown in below. Show the results of the follow

Question

Consider the two tables 71 and 72 shown in below. Show the results of the following operations: T1 T1.p = T2.A T2 T1 T1.Q = T2.B T2 T1 u T2 T1 (T1 .P = T2.A AND T1.R = T2.C) T2 Consider the ER diagram shown in Figure 7.21 for part of a BANK database. Each bank can have multiple branches, and each branch can have multiple accounts and loans. List the strong (nonweak) entity types in the ER diagram. Is there a weak entity type? If so, give its name, its partial key, and its identifying relationship. What constraints do the partial key and the identifying relationship of the weak entity type specify in this diagram? 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. List concisely the user requirements that led to this ER schema design. 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 1000 loans. How does this show up on the (min.max) constraints?

Explanation / Answer

Hi,

The solution for 7.23 is below. Hope it Helps :D

a. Bank , Account, Customer, Loan

b. Yes, Bank Branch. Partial key is Branch_no , identifying relationship is Branches.

c. Every bank branch (identified by branch number) should have a bank (otherwise it cannot exist) ,

and a bank can have any number of branches. It means that a branch can be uniquely identied only

using both Branch_No and Bank Code.   

d. one to many and many to many are the relationship types.

Bank (0,n) -- branches -- (1,1) Bank_Branch

Branch (0,m) -- accounts -- (0,1) Account

Account (0,n) -- a_c -- (0,m) Customer

Bank_Branch (0,n) --Loans --(0,1) Bank_Branch

Customer (0,m) --- L_C --- (0,n) Loan

e.

Account (0,n) -- a_c -- (1,m) Customer

Customer (0,2) --- L_C --- (0,n) Loan

Bank_Branch (0,1000) --Loans --(0,1) Bank_Branch

For 6.22 , find your solution here.

http://www.chegg.com/homework-help/questions-and-answers/622-consider-tables-t1-t2-shown-figure-613-results-thefollowing-operations--t1-tx-tlp-t2-t-q971219

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.