Data Collection and DBMS Practice MCQs

Question 1

A college keeps admissions.csv and exam_results.csv. Ravi's new phone number was typed only into exam_results.csv, so the two files now show different numbers for him. Which file-system problem does this illustrate?

Accepted Answer

B. Data inconsistency

Answer

Data isolation

Answer

Data inconsistency

Answer

Program–data dependence

Answer

Concurrent-access anomaly

Question 2

A college adds an email column to admissions.csv and must then rewrite every program that parses that file. Which limitation of the file-based approach is this?

Accepted Answer

B. Program–data dependence

Answer

Data redundancy

Answer

Program–data dependence

Answer

Data isolation

Answer

Integrity problem

Question 3

A fee program writes 'paid' into fees.csv and then crashes before writing the matching entry into receipts.csv. Which problem is this, and what DBMS service prevents it?

Accepted Answer

C. Atomicity problem; a transaction with log-based recovery undoes the partial change

Answer

Data isolation; a shared file format lets the two files be combined later

Answer

Security problem; column-level privileges hide the fee file from other users

Answer

Atomicity problem; a transaction with log-based recovery undoes the partial change

Answer

Redundancy problem; storing the fee in a single file removes the crash risk

Question 4

In which situation is a plain file most reasonably preferred over a DBMS?

Accepted Answer

C. A single-user script that appends lines to its own log file

Answer

Account balances updated by many bank tellers at the same time

Answer

A railway reservation system shared by thousands of booking agents

Answer

A single-user script that appends lines to its own log file

Answer

A results database shared by the exam, fees and admission offices

Question 5

Which DBMS module translates a SELECT statement and chooses an efficient execution plan for it?

Accepted Answer

A. DML compiler and query optimizer

Answer

DML compiler and query optimizer

Answer

Buffer manager

Answer

Authorization and integrity manager

Answer

Transaction manager

Question 6

A DBA inserts 500 new rows into the student table and later adds a date_of_birth column to it. Which statement is correct?

Accepted Answer

B. The inserts change the instance; adding the column changes the schema

Answer

Both actions change only the schema of the student table

Answer

The inserts change the instance; adding the column changes the schema

Answer

The inserts change the schema; adding the column changes the instance

Answer

Both actions change only the instance of the student table

Question 7

A DBA adds an index on member.email and moves the member table to faster disks. No query, view or application has to change. Which property does this demonstrate?

Accepted Answer

D. Physical data independence

Answer

Logical data independence

Answer

Distribution independence

Answer

Integrity independence

Answer

Physical data independence

Question 8

Why is logical data independence harder to achieve than physical data independence?

Accepted Answer

A. Conceptual-schema changes can alter what the data means to programs

Answer

Conceptual-schema changes can alter what the data means to programs

Answer

Indexes cannot be added without rewriting the application queries

Answer

The internal storage level is directly visible to every end user

Answer

Views can never hide any change made to the underlying base tables

Question 9

SELECT email FROM member WHERE member_id = 102; retrieves one value using only a table name, a primary-key value and a column name. Which of Codd's rules does this illustrate?

Accepted Answer

C. Guaranteed access rule

Answer

Information rule

Answer

Physical data independence

Answer

Guaranteed access rule

Answer

Comprehensive data sublanguage rule

Question 10

Table member(member_id PRIMARY KEY, full_name, email, phone, status) holds 101 'Asha Patil' (phone '9876500001'), 102 'Ravi Kumar' (phone NULL) and 103 'Meera Iyer' (phone NULL). What does SELECT COUNT(*) FROM member WHERE phone = NULL; return?

Accepted Answer

D. 0

Answer

3

Answer

2

Answer

1

Answer

0

Question 11

Which MySQL practice best reflects Codd's Rule 4, the dynamic online catalog based on the relational model?

Accepted Answer

B. Querying information_schema.COLUMNS with an ordinary SELECT

Answer

Running mysqldump to export the table definitions into a text file

Answer

Querying information_schema.COLUMNS with an ordinary SELECT

Answer

Keeping table definitions in a separate XML configuration file

Answer

Reading the server error log to discover the names of tables

Question 12

UPDATE member SET status = 'INACTIVE' WHERE phone IS NULL; changes every matching row (two rows here) in one statement. Which of Codd's rules does this set-at-a-time behaviour illustrate?

Accepted Answer

A. High-level insert, update and delete

Answer

High-level insert, update and delete

Answer

View updating rule

Answer

Nonsubversion rule

Answer

Systematic treatment of NULL values

Question 13

A product offers a low-level record-at-a-time API that writes directly to storage and skips the foreign-key checks declared in SQL. Which of Codd's rules does this violate?

Accepted Answer

A. Nonsubversion rule

Answer

Nonsubversion rule

Answer

Distribution independence

Answer

Guaranteed access rule

Answer

Integrity independence

Question 14

A team drops the CHECK (marks BETWEEN 0 AND 100) constraint and instead validates marks separately inside each Java and Python program. Which of Codd's rules does this move away from?

Accepted Answer

D. Integrity independence

Answer

Information rule

Answer

View updating rule

Answer

Distribution independence

Answer

Integrity independence

Question 15

At a railway counter, a clerk books tickets only by filling in fields on a reservation screen and never writes queries. Which type of database user is the clerk?

Accepted Answer

A. Naive (parametric) end user

Answer

Naive (parametric) end user

Answer

Casual or sophisticated user

Answer

Application programmer

Answer

Database administrator

Data Collection and DBMS Practice MCQs

Data Collection and DBMS Free MCQs

A college keeps admissions.csv and exam_results.csv. Ravi's new phone number was typed only into exam_results.csv, so the two files now show different numbers for him. Which file-system problem does this illustrate?

A college adds an email column to admissions.csv and must then rewrite every program that parses that file. Which limitation of the file-based approach is this?

A fee program writes 'paid' into fees.csv and then crashes before writing the matching entry into receipts.csv. Which problem is this, and what DBMS service prevents it?

In which situation is a plain file most reasonably preferred over a DBMS?

Which DBMS module translates a SELECT statement and chooses an efficient execution plan for it?

A DBA inserts 500 new rows into the student table and later adds a date_of_birth column to it. Which statement is correct?

A DBA adds an index on member.email and moves the member table to faster disks. No query, view or application has to change. Which property does this demonstrate?

Why is logical data independence harder to achieve than physical data independence?

SELECT email FROM member WHERE member_id = 102; retrieves one value using only a table name, a primary-key value and a column name. Which of Codd's rules does this illustrate?

Table member(member_id PRIMARY KEY, full_name, email, phone, status) holds 101 'Asha Patil' (phone '9876500001'), 102 'Ravi Kumar' (phone NULL) and 103 'Meera Iyer' (phone NULL). What does SELECT COUNT(*) FROM member WHERE phone = NULL; return?

Which MySQL practice best reflects Codd's Rule 4, the dynamic online catalog based on the relational model?

UPDATE member SET status = 'INACTIVE' WHERE phone IS NULL; changes every matching row (two rows here) in one statement. Which of Codd's rules does this set-at-a-time behaviour illustrate?

A product offers a low-level record-at-a-time API that writes directly to storage and skips the foreign-key checks declared in SQL. Which of Codd's rules does this violate?

A team drops the CHECK (marks BETWEEN 0 AND 100) constraint and instead validates marks separately inside each Java and Python program. Which of Codd's rules does this move away from?

At a railway counter, a clerk books tickets only by filling in fields on a reservation screen and never writes queries. Which type of database user is the clerk?

Codd's rules are numbered 0 to 12. What does Rule 0, the foundation rule, require?

loan.member_id is declared as FOREIGN KEY (member_id) REFERENCES member(member_id) with no ON DELETE option, and loan 1 refers to member 101. In MySQL (InnoDB), what happens when DELETE FROM member WHERE member_id = 101; runs?

In student(roll_no, email, aadhaar_no, name), each of roll_no, email and aadhaar_no is unique and never NULL, and roll_no is chosen as the primary key. What are email and aadhaar_no called?

No member with member_id 999 exists, and INSERT INTO loan VALUES (3, 999, 'Unknown Member Book', '2026-02-12'); is rejected by the DBMS. Which kind of integrity is being enforced?

In formal relational theory a relation is a set of tuples. Which statement correctly contrasts this with practical SQL tables?

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