Question

can be overcome by relational DBMS?
d) Consider the table given below:
Table: courses
Classid
Title
classnum
1001
Intro to information
1101
1002
Computer applications 1400
1003
Internet and seciety
1400
Identify the Primary key in all the tables.
Can classnum colum will be primary key ?state reason.​

Answer 1

Answer:

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Answer 2

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Explanation:

value must uniquely identify the corresponding row in table. BankAccount_Number is not a candidate key. As per the question “A student can have multiple accounts or joint accounts. This attributes stores the primary account number”. If two students have a joint account and if the joint account is their primary account, then BankAccount_Number value cannot uniquely identify a row.

2) Consider a relational table r with sufficient number of records, having attributes A1, A2,…, An and let 1

The database can be configured to do ordered indexing on Ap or hashing on Ap. Which of the following statements is TRUE?

(A) Ordered indexing will always outperform hashing for both queries

(B) Hashing will always outperform ordered indexing for both queries

(C) Hashing will outperform ordered indexing on Q1, but not on Q2

(D) Hashing will outperform ordered indexing on Q2, but not on Q1.

Answer (C)

If record are accessed for a particular value from table, hashing will do better. If records are accessed in a range of values, ordered indexing will perform better. See this for more details.

3) Database table by name Loan_Records is given below.

Borrower Bank_Manager Loan_Amount

Ramesh Sunderajan 10000.00

Suresh Ramgopal 5000.00

Mahesh Sunderajan 7000.00

What is the output of the following SQL query?

SELECT Count(*)

FROM ( (SELECT Borrower, Bank_Manager

FROM Loan_Records) AS S

NATURAL JOIN (SELECT Bank_Manager,

Loan_Amount

FROM Loan_Records