Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
Match records using defined identity attributes and retain or merge according to survivorship rules
B.
Round every numeric measure to an integer
C.
Replace all customer names with surrogate keys
D.
Delete every record containing the same city
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Correct Answer: A. Match records using defined identity attributes and retain or merge according to survivorship rules
Explanation:
Duplicate resolution requires matching criteria and rules for selecting trusted values.
Choose an option to check your answer.
A.
To make it immediately editable by all report users
B.
To serve as the final dimensional model
C.
To eliminate source-to-target mappings
D.
To preserve a controllable copy for validation, reconciliation, and restart
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Correct Answer: D. To preserve a controllable copy for validation, reconciliation, and restart
Explanation:
Staging decouples source access from downstream processing.
Choose an option to check your answer.
A.
The largest fact amount is removed from each batch
B.
Every source column is converted to a percentage
C.
The last successfully processed timestamp or sequence is saved for the next extraction
D.
The dashboard displays only peak values
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Correct Answer: C. The last successfully processed timestamp or sequence is saved for the next extraction
Explanation:
A watermark defines the boundary between previously loaded and new records.
Choose an option to check your answer.
A.
A list of dashboard users
B.
A record of source inserts, updates, and deletes that occurred after a point in time
C.
A prebuilt star schema
D.
A method for choosing chart colors
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Correct Answer: B. A record of source inserts, updates, and deletes that occurred after a point in time
Explanation:
CDC exposes data changes so the warehouse can load them incrementally.
Choose an option to check your answer.
A.
It processes only new or changed source records
B.
It guarantees that source data contains no errors
C.
It eliminates the need for a staging area
D.
It removes all historical rows from the target
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Correct Answer: A. It processes only new or changed source records
Explanation:
Incremental loads reduce data movement and processing time.
Choose an option to check your answer.
A.
When only one new row must be loaded
B.
When source systems expose reliable change tracking
C.
When the load window is too small for all rows
D.
When the complete source dataset is small enough or changes cannot be identified reliably
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Correct Answer: D. When the complete source dataset is small enough or changes cannot be identified reliably
Explanation:
A full extraction retrieves all relevant source records each cycle.
Choose an option to check your answer.
A.
Evaluate, Test, and Log
B.
Encrypt, Transfer, and Lock
C.
Extract, Transform, and Load
D.
Explore, Tag, and Link
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Correct Answer: C. Extract, Transform, and Load
Explanation:
ETL moves data from source systems into an analytical target.
Choose an option to check your answer.
A.
Change the business meaning of a requested measure
B.
Choose an execution strategy with low estimated resource cost while preserving correct results
C.
Return approximate rows without user knowledge
D.
Force every query to use the newest index
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Correct Answer: B. Choose an execution strategy with low estimated resource cost while preserving correct results
Explanation:
The optimizer compares valid access, join, and aggregation alternatives.
Choose an option to check your answer.
A.
When measured query benefits outweigh redundancy and maintenance costs
B.
Whenever a source table has a primary key
C.
To make business definitions less consistent
D.
To prevent all incremental loads
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Correct Answer: A. When measured query benefits outweigh redundancy and maintenance costs
Explanation:
Physical design can duplicate or prejoin data to reduce expensive query operations.
Choose an option to check your answer.
A.
To capture each source transaction before validation
B.
To store user passwords separately
C.
To replace all detailed facts permanently
D.
To pre-summarize data for frequently requested query levels
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Correct Answer: D. To pre-summarize data for frequently requested query levels
Explanation:
Aggregate tables reduce the number of detailed rows processed for common summaries.
Choose an option to check your answer.
A.
Normalize every dimension into many tables
B.
Remove surrogate keys from facts
C.
Efficiently filter a large fact table using selective dimension predicates
D.
Force all joins to use nested loops
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Correct Answer: C. Efficiently filter a large fact table using selective dimension predicates
Explanation:
Star queries combine a very large fact table with smaller dimensions.
Choose an option to check your answer.
A.
Table scan
B.
Index seek
C.
Hash spill
D.
Cube process full
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Correct Answer: B. Index seek
Explanation:
A seek navigates the index structure to qualifying keys.
