Data Warehousing and Business Intelligence MCQs

The clustered index determines the logical order of data pages by its key.
A table can have only one clustered organization at a time.

An indexed view stores its result physically and can avoid repeated computation.
Its maintenance cost and SQL Server restrictions must be evaluated carefully.

Standardization converts equivalent source representations into a common format.
It improves grouping, matching, and consistency across systems.

Data quality is evaluated through several complementary characteristics.
A dataset can be accurate but still incomplete, late, inconsistent, or duplicated.

Roll-up aggregates data to a higher level in a hierarchy.
Monthly members are summarized into their parent year totals.

GROUP BY partitions detail rows into logical groups for aggregate functions.
It is commonly used to summarize facts by dimensions such as month or region.

A star schema places measurable events at the center and descriptive dimensions around them.
Its simple joins make analytical models understandable and efficient.

A nonclustered index is a separate access structure from the table data.
It helps SQL Server locate qualifying rows without scanning the full table.

Complex joins and aggregations may require work space beyond available memory.
Proper tempdb sizing and I/O design reduce contention and spill penalties.

Missing values can mean unknown, not applicable, delayed, or erroneous.
Treatment must preserve meaning and be documented for users.

Fuzzy matching scores similarity across names, addresses, dates, and other fields.
Thresholds and review rules are needed to control false matches.

Drill-down navigates from summarized levels toward finer detail.
The hierarchy provides the path from Year to Quarter to Month.