Database Management & Information Systems Flashcards

Which concurrency control technique uses shared and exclusive locks to prevent conflicting database operations?

Answer: Two-phase locking (2PL)

Two-phase locking grants shared locks for reads and exclusive locks for writes, releasing them only after the transaction commits.

A view in a relational database is best described as:

Answer: A virtual table based on a stored SQL query

A view is a named, stored SELECT statement that presents data from one or more tables without storing the data itself.

Which data model represents data as a collection of nodes and edges, making it ideal for social networks and recommendation engines?

Answer: Graph model

Graph databases store data as nodes (entities) and edges (relationships), efficiently traversing highly connected datasets.

What does the ACID property 'Isolation' guarantee?

Answer: Concurrent transactions do not interfere with each other

Isolation ensures that the intermediate state of a transaction is invisible to other concurrently running transactions.

In database design, what is a surrogate key?

Answer: A system-generated, meaningless unique identifier

A surrogate key is an artificially generated identifier (e.g., auto-increment integer) with no business meaning.

Which SQL command is used to remove all rows from a table quickly without logging individual row deletions?

Answer: TRUNCATE

TRUNCATE removes all rows from a table rapidly by deallocating data pages rather than logging each row deletion.

In an information system, the 'processing' component refers to:

Answer: Converting raw input into meaningful output

Processing transforms raw data through calculations, sorting, or logic into information useful for decision-making.