Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
A predicate identifies a relatively small fraction of table rows
B.
Every value in the indexed column is identical
C.
The index contains no key columns
D.
The query returns the entire table
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Correct Answer: A. A predicate identifies a relatively small fraction of table rows
Explanation:
Selective predicates narrow the search to few rows.
Choose an option to check your answer.
A.
Scanning billions of rows for grouped totals
B.
Compressing repeated values in a large fact column
C.
Batch-mode aggregation across many segments
D.
Highly selective point lookups and small-row transactional access
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Correct Answer: D. Highly selective point lookups and small-row transactional access
Explanation:
Rowstore indexes efficiently navigate to a small number of matching rows.
Choose an option to check your answer.
A.
Frequent updates to one narrow row using a unique key
B.
Storage of image files in a transaction table
C.
Large analytical scans and aggregations over a fact table
D.
Single-character lookup in a tiny code table
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Correct Answer: C. Large analytical scans and aggregations over a fact table
Explanation:
Columnstore organizes and compresses data by column and processes it in batches.
Choose an option to check your answer.
A.
When every query scans all historical rows
B.
When queries repeatedly target a small, well-defined subset of rows
C.
When the table contains no predicates
D.
When users need a new chart type
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Correct Answer: B. When queries repeatedly target a small, well-defined subset of rows
Explanation:
A filtered index stores only rows matching a condition such as Active = 1.
Choose an option to check your answer.
A.
The leading columns determine which search predicates and sort orders can use the index efficiently
B.
SQL Server sorts the key columns alphabetically at runtime
C.
Only the last key column can be filtered
D.
Column order changes the business meaning of stored facts
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Correct Answer: A. The leading columns determine which search predicates and sort orders can use the index efficiently
Explanation:
B-tree navigation is most effective from the leftmost key prefix.
Choose an option to check your answer.
A.
When it includes every column in the database
B.
When its key is encrypted
C.
When it is rebuilt every hour
D.
When it contains all columns needed to satisfy the query without accessing the base table
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Correct Answer: D. When it contains all columns needed to satisfy the query without accessing the base table
Explanation:
A covering index supplies the filter, join, and output columns required by a query.
Choose an option to check your answer.
A.
A complete replacement for the base table in every case
B.
Only database security settings
C.
Ordered key values with locators to the underlying table rows
D.
OLAP cube aggregations
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Correct Answer: C. Ordered key values with locators to the underlying table rows
Explanation:
A nonclustered index is a separate access structure from the table data.
Choose an option to check your answer.
A.
It creates a separate copy containing every column automatically
B.
It organizes the table’s data rows according to the clustered key
C.
It prevents range queries
D.
It can exist in unlimited numbers on one table
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Correct Answer: B. It organizes the table’s data rows according to the clustered key
Explanation:
The clustered index determines the logical order of data pages by its key.
Choose an option to check your answer.
A.
The measurable business process being analyzed
B.
The alphabetical order of source tables
C.
The preferred dashboard color
D.
The number of developers on the project
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Correct Answer: A. The measurable business process being analyzed
Explanation:
Dimensional design begins with a business process such as sales, claims, or shipments.
Choose an option to check your answer.
A.
To increase the number of dimension rows for performance
B.
To replace all null descriptive attributes
C.
To store ETL source code
D.
To preserve referential integrity when a source key is missing or unmatched
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Correct Answer: D. To preserve referential integrity when a source key is missing or unmatched
Explanation:
Unknown members provide a valid key when business context cannot be resolved.
Choose an option to check your answer.
A.
A Type 1 overwrite of both representatives
B.
Removing the sales amount from the fact table
C.
Allocation weights whose total equals the full fact amount
D.
Creating unrelated copies of the fact
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Correct Answer: C. Allocation weights whose total equals the full fact amount
Explanation:
Bridge rows can carry weights that distribute one fact across multiple members.
Choose an option to check your answer.
A.
A measure stored outside the database
B.
A secondary dimension referenced from another dimension rather than directly from the fact
C.
A staging table used for file imports
D.
A report that contains no visuals
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Correct Answer: B. A secondary dimension referenced from another dimension rather than directly from the fact
Explanation:
An outrigger normalizes a reusable set of dimension attributes outside the main dimension.
