121. Which analytical function calculates running totals?
- a) SUM() OVER()
- b) RUNNING_TOTAL()
- c) CUMULATE()
- d) AGGREGATE()
Answer: A - SUM(column) OVER(ORDER BY sort_column) computes cumulative sums.
122. What is the purpose of database auditing?
- a) Tracks data access and changes
- b) Optimizes performance
- c) Compresses backups
- d) Validates schemas
Answer: A - Auditing maintains security logs for compliance (e.g., AUDIT SELECT ON table).
123. Which SQL feature implements blockchain-like tables?
- a) Immutable ledger tables
- b) Blockchain extensions
- c) Hash-chain constraints
- d) CryptoTables
Answer: A - Oracle 21c+ and SQL Server 2022+ offer tamper-evident ledger tables.
124. What is a time travel query?
- a) Retrieves historical data at past points
- b) Measures query duration
- c) Replays transactions
- d) Synchronizes clocks
Answer: A - Snowflake and Oracle Flashback Query enable historical snapshots.
125. Which graph database function finds shortest paths?
- a) SHORTEST_PATH()
- b) FIND_ROUTE()
- c) TRAVERSE()
- d) CONNECT_BY()
Answer: A - Graph extensions in Oracle/PG use SHORTEST_PATH syntax.
126. What is the purpose of the SQL PERCENTILE_CONT() function?
- a) Computes continuous percentiles
- b) Counts distinct values
- c) Groups by percentage
- d) Samples data
Answer: A - Calculates interpolated values at specified percentiles (e.g., median).
127. Which statement enables change tracking?
- a) ALTER DATABASE ENABLE CHANGE_TRACKING
- b) START TRACKING CHANGES
- c) CREATE CHANGE_LOG
- d) ENABLE VERSIONING
Answer: A - Tracks DML changes for sync applications (SQL Server feature).
128. What is the purpose of the SQL FIRST_VALUE() function?
- a) Returns first value in window frame
- b) Finds initial table row
- c) Gets oldest record
- d) Retrieves creation timestamp
Answer: A - Window function that accesses the first row in a partition.
129. Which feature automatically classifies sensitive data?
- a) Data Discovery & Classification
- b) Smart Tags
- c) Sensitivity Labels
- d) Auto-Categorization
Answer: A - SQL Server and Azure SQL can detect PII/PCI data patterns.
130. What is the purpose of the SQL GENERATE_SERIES() function?
- a) Creates number/date sequences
- b) Generates test data
- c) Outputs result sets
- d) Replicates rows
Answer: A - PostgreSQL/SQL Server 2022+ function for sequence generation.
131. Which statement creates a temporal table?
- a) CREATE TABLE...WITH SYSTEM_VERSIONING
- b) MAKE TEMPORAL TABLE
- c) CREATE HISTORY TABLE
- d) DEFINE VERSIONED TABLE
Answer: A - Automatically maintains historical versions of rows.
132. What is the purpose of the SQL LISTAGG() function?
- a) Concatenates string values
- b) Lists table columns
- c) Aggregates arrays
- d) Generates XML
Answer: A - Oracle's string aggregation function (similar to STRING_AGG).
133. Which database supports time-series extensions?
- a) TimescaleDB
- b) InfluxDB
- c) Prometheus
- d) All of the above
Answer: D - Specialized databases for timestamped data analysis.
134. What is the purpose of the SQL CUME_DIST() function?
- a) Calculates cumulative distribution
- b) Measures distance
- c) Computes averages
- d) Counts distincts
Answer: A - Returns relative position (0-1) of a value within a window.
135. Which statement creates a columnstore index?
- a) CREATE COLUMNSTORE INDEX
- b) MAKE COLUMN INDEX
- c) ADD COLUMNSTORE
- d) DEFINE COLUMNAR INDEX
Answer: A - Optimized for analytics workloads (SQL Server feature).
136. What is the purpose of the SQL APPROX_PERCENTILE() function?
- a) Estimates percentiles with reduced accuracy
- b) Calculates exact percentiles
- c) Samples random data
- d) Groups by percentage
Answer: A - Uses approximation algorithms for big data efficiency.
137. Which feature enables zero-downtime migrations?
- a) Database mirroring
- b) Log shipping
- c) Always On Availability Groups
- d) All of the above
Answer: D - High-availability technologies minimize downtime during upgrades.
138. What is the purpose of the SQL WIDTH_BUCKET() function?
- a) Assigns values to equi-width histogram bins
- b) Measures column sizes
- c) Calculates storage requirements
- d) Partitions tables
Answer: A - Useful for data distribution analysis (Oracle/PostgreSQL).
139. Which database provides built-in graph algorithms?
- a) Neo4j
- b) Oracle PGX
- c) SQL Server Graph
- d) All of the above
Answer: D - Offer pathfinding, centrality, and community detection.
140. What is the purpose of the SQL BIT_AND() function?
- a) Performs bitwise AND across rows
- b) Combines binary data
- c) Encrypts values
- d) Compresses bitmaps
Answer: A - Aggregate function for bitmask operations (MySQL/PostgreSQL).