Data-Management-Foundations Reviews Questions

Anindex scanis a database operation thatquickly locates table blocksusing anindexrather than scanning the entire table. It significantly improves query performance.

Example Usage:

sql

SELECT * FROM Employees WHERE EmployeeID = 105;

If EmployeeID isindexed, the database uses anindex scantoquickly find the record.

Why Other Options Are Incorrect:

Option A (Binary search) (Incorrect):A searching algorithm, but not a database operation.

Option B (Table scan) (Incorrect):Scans theentire table, which isslowerthan an index scan.

Option C (Fan-out) (Incorrect):Refers tobranching in B-Treesbut doesnot locate table blocks directly.

Thus, the correct answer isIndex scan, as it efficiently locates table blocks.

ADatabase Administrator (DBA)is responsible for the management, security, and performance of a database system. This includes controlling access to data, ensuring database integrity, optimizing performance, managing backups, and protecting the system from unauthorized access.

Option A (Incorrect):A DBA is not just a consumer of data but is primarily responsible for the database’s management.

Option B (Correct):Security is one of the key responsibilities of a DBA, including enforcing user access controls and implementing encryption and authentication mechanisms.

Option C (Incorrect):While DBAs work with data structures, it is typically the role of adata architectordatabase designerto define data formats and schema structures.

Option D (Incorrect):Developing application programs that interact with the database is typically the role ofsoftware developersordatabase programmers, not DBAs.

ATransaction ManagerensuresACID (Atomicity, Consistency, Isolation, Durability)properties in database transactions. It manages concurrent transactions, ensuring no conflicts occur and logs modifications to support recovery mechanisms.

Option A (Incorrect):Query optimization is managed by thequery processor, not the transaction manager.

Option B (Incorrect):The transaction manager is a component of the database architecture but is not composed of the entire system (query processor, storage manager, etc.).

Option C (Correct):The transaction manager logs transactions like INSERT, UPDATE, and DELETE, ensuring consistency and recoverability.

Option D (Incorrect):Thestorage manageris responsible for translating queries into filesystem commands.

Aquery processoris responsible forquery optimization and executionin a database management system (DBMS). It analyzes SQL statements, optimizes execution plans, and ensures efficient retrieval of data.

Option A (Correct):Thequery processoroptimizes queries by analyzing metadata from thesystem catalogto determine the best execution strategy.

Option B (Incorrect):Logging transactionsbefore applying changes is the responsibility of thetransaction manager.

Option C (Incorrect):Translating instructions intofile system commandsis handled by thestorage manager, not the query processor.

Option D (Incorrect):While the query processor helps retrieve results, thedatabaseengineandAPI layerare responsible for returning results to applications.