ICT Database Management Concepts 3

Question 1

What is a deadlock in database management?

Accepted Answer

A situation where two transactions wait indefinitely for each other's locked resources

Answer

A deadlock occurs when two or more transactions each hold locks the others need, causing all to wait forever.

Question 2

Which database model stores data as collections of key-value pairs, documents, or graphs?

Accepted Answer

NoSQL database

Answer

NoSQL databases use non-tabular storage models such as key-value, document, column-family, or graph formats.

Question 3

What does the SQL keyword DISTINCT do in a SELECT statement?

Accepted Answer

Returns only unique values, eliminating duplicates

Answer

DISTINCT ensures only unique rows are returned by removing duplicate values from query results.

Question 4

In a database context, what is a view?

Accepted Answer

A virtual table based on the result of a SQL query

Answer

A view is a stored SQL query that presents data from one or more tables as if it were a single virtual table.

Question 5

Which concurrency control technique uses timestamps to order transactions?

Accepted Answer

Timestamp-based protocol

Answer

The timestamp-based protocol assigns timestamps to transactions and uses them to determine the serialization order.

ICT - Information Communication Technology Practice Test