Database Technologies Practice MCQs

Question 1

Which statement best describes a DBMS?

Accepted Answer

A. Software that defines, stores, queries, protects and recovers a database

Answer

Software that defines, stores, queries, protects and recovers a database

Answer

The collection of data files that holds the stored rows on disk

Answer

The declarative language used to write queries against tables

Answer

A diagram that shows entities, attributes and their relationships

Question 2

What is a database schema?

Accepted Answer

A. The definition of tables, columns, keys and constraints

Answer

The definition of tables, columns, keys and constraints

Answer

All rows stored in the tables at one particular moment

Answer

The running database server process on a host machine

Answer

A saved result set produced by an earlier SELECT query

Question 3

A clerk inserts 50 new rows into the existing LOAN table without changing its columns. In data-model terms, what has changed?

Accepted Answer

C. Only the instance (stored contents)

Answer

Only the schema of the LOAN table

Answer

Both the schema and the instance

Answer

Only the instance (stored contents)

Answer

Nothing until the server is restarted

Question 4

In a CUSTOMER table, what does one row represent?

Accepted Answer

A. One customer occurrence, i.e. one tuple

Answer

One customer occurrence, i.e. one tuple

Answer

One attribute shared by all customers

Answer

The data type of one customer column

Answer

The full set of customer constraints

Question 5

In the three-schema (ANSI/SPARC) architecture, which level describes physical storage structures and access paths?

Accepted Answer

D. Internal level

Answer

External level

Answer

Conceptual level

Answer

View level

Answer

Internal level

Question 6

A MySQL table is created with no PRIMARY KEY or UNIQUE constraint. What happens when exactly the same column values are inserted twice?

Accepted Answer

Both rows are stored as duplicate rows

Answer

The second insert is rejected automatically

Answer

MySQL merges the two inserts into one row

Answer

The second row silently replaces the first

Question 7

Which data model describes business entities, relationships and rules before any DBMS or storage decision is made?

Accepted Answer

D. Conceptual model

Answer

Physical model

Answer

Logical model

Answer

Internal schema

Answer

Conceptual model

Question 8

Which data model specifies indexes, storage engines, partitions and vendor-specific data types?

Accepted Answer

C. Physical model

Answer

Conceptual model

Answer

Logical model

Answer

Physical model

Answer

External view

Question 9

What does data independence aim to reduce?

Accepted Answer

A. The impact of lower-level schema changes on higher levels

Answer

The impact of lower-level schema changes on higher levels

Answer

The amount of redundant data stored across tables

Answer

The number of users who may connect at the same time

Answer

The time the server needs to recover after a crash

Question 10

Which MySQL client provides a graphical interface for SQL editing, schema browsing and ER modelling?

Accepted Answer

D. MySQL Workbench

Answer

mysql command-line monitor

Answer

MySQL Shell (mysqlsh)

Answer

mysqldump utility

Answer

MySQL Workbench

Question 11

In MySQL's client-server architecture, which component parses, optimizes and executes a submitted SQL statement?

Accepted Answer

C. The MySQL server process (mysqld)

Answer

MySQL Workbench

Answer

The mysql command-line client

Answer

The MySQL server process (mysqld)

Answer

The operating system's file manager

Question 12

Column names, data types, constraints and privileges that the DBMS records about its tables are examples of what?

Accepted Answer

B. Metadata held in the data dictionary

Answer

Instance data stored in user tables

Answer

Metadata held in the data dictionary

Answer

Derived attributes computed by queries

Answer

Transaction log records for recovery

Question 13

Two clerks update the same account balance at the same moment. Which DBMS service prevents their changes from corrupting each other?

Accepted Answer

A. Concurrency control

Answer

Concurrency control

Answer

Query optimization

Answer

Data dictionary management

Answer

Physical data independence

Question 14

After a power failure, which DBMS service uses logs to keep committed changes and remove incomplete ones?

Accepted Answer

B. Recovery

Answer

Authorization

Answer

Recovery

Answer

Query parsing

Answer

Normalization

Question 15

Which database object gives a user a selected perspective, such as hiding salary columns, without storing a separate copy of the rows?

Accepted Answer

C. View

Answer

Index

Answer

Temporary table

Answer

View

Answer

Trigger

Database Technologies Practice MCQs

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