Data Warehousing Questions and Answers

Q: A subset of data in a data warehouse in the form of summary data, related to a particular department or business function :

The answer is Data Marts.A data mart is a subset of the data warehouse, usually summarised, that serves one department or business function, such as sales or finance. It gives those users faster and simpler access to the data they need.Metadata is data about the warehouse's data, archive data is old data kept for the record, and an operational data store holds current, detailed operational data rather than departmental summaries.

Q: The @active data warehouse architecture includes which of the following?

Correct answer: All of the above.The active warehouse architecture is distinguished by near real-time updating, which is what allows it to support operational decisions rather than only strategic ones. It retains the features of the earlier architectures - extraction from many internal and external sources, and dependent data marts for particular user groups.

Q: A goal of data mining includes which of the following?

Correct answer: To explain some observed event or conditionData mining is exploratory: it looks for patterns and relationships that were not anticipated, and so can suggest why something happened. This is what distinguishes it from ordinary querying, which confirms relationships already expected - the second and third options describe verification rather than discovery.

Q: A data warehouse is which of the following?

Correct answer: Organized around important subject areas.Subject orientation is the first of the defining characteristics: the warehouse is arranged around customer, product or sale rather than around the applications the data came from. The other options describe an operational system - it is the warehouse that is integrated, non-volatile and time-variant.

Q: A snowflake schema is which of the following types of tables?

Correct answer: All of the aboveA snowflake schema is a star in which the dimension tables have themselves been normalised, so the dimensions are split into further tables. Fact, dimension and helper tables therefore all appear. The advantage is reduced redundancy; the cost is more joins and slower queries.

Q: Fact tables are which of the following?

Correct answer: Completely normalizedThe fact table holds the measures and the foreign keys to the dimensions, and nothing that could be moved elsewhere - so it is fully normalised. It is the dimension tables that are deliberately denormalised, since flattening them reduces the joins a query must perform, at a cost in redundancy that a read-only store can afford.

Which of the given options best describes the truthfulness of the following statements?

i) The 'communications', 'Schedules' and 'Task lists' are key functionality aspects of project management software to guide you in your decision.
ii) A data warehouse is a relational database that is designed for query and analysis rather than transaction processing.
iii) Software integration option is one of the criteria for selecting project management software.

A.i-True, ii-True, iii-True
B.i-False, ii-True, iii-True
C.i-True, ii-True, iii-False
D.i-True, ii-False, iii-True

Exam Year(s)

DSSSB TGT - 2023,

Answer: A

All three statements are true. Communications, schedules and task lists are key functionality aspects of project management software, a data warehouse is a relational database designed for query and analysis and not for transaction processing, and software integration is one of the criteria for selecting such software. So the first option is correct and the options that mark any statement false are wrong. Statement ii separates a data warehouse from an ordinary operational database, which is built for transactions.

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A subset of data in a data warehouse in the form of summary data, related to a particular department or business function :

A.Meta data
B.Archive data
C.Data Marts
D.Operational Data Store

Exam Year(s)

Tripura Public Service Commission - 2019,

Answer: C

The answer is Data Marts.

A data mart is a subset of the data warehouse, usually summarised, that serves one department or business function, such as sales or finance. It gives those users faster and simpler access to the data they need.

Metadata is data about the warehouse's data, archive data is old data kept for the record, and an operational data store holds current, detailed operational data rather than departmental summaries.

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Data scrubbing is which of the following?

A.A process to reject data from the data warehouse and to create the necessary indexes
B.A process to load the data in the data warehouse and to create the necessary indexes
C.A process to upgrade the quality of data after it is moved into a data warehouse
D.A process to upgrade the quality of data before it is moved into a data warehouse

Answer: D

Correct answer: A process to upgrade the quality of data before it is moved into a data warehouse

Scrubbing happens on the way in, during the transformation stage, because the warehouse is meant to be the trustworthy source and cleaning it afterwards would mean queries had already run against bad data. It corrects misspellings, resolves conflicting codes and fills or flags missing values.

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The @active data warehouse architecture includes which of the following?

A.At least one data mart
B.Data that can extracted from numerous internal and external sources
C.Near real-time updates
D.All of the above.

Answer: D

Correct answer: All of the above.

The active warehouse architecture is distinguished by near real-time updating, which is what allows it to support operational decisions rather than only strategic ones. It retains the features of the earlier architectures - extraction from many internal and external sources, and dependent data marts for particular user groups.

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A goal of data mining includes which of the following?

A.To explain some observed event or condition
B.To confirm that data exists
C.To analyze data for expected relationships
D.To create a new data warehouse

Answer: A

Correct answer: To explain some observed event or condition

Data mining is exploratory: it looks for patterns and relationships that were not anticipated, and so can suggest why something happened. This is what distinguishes it from ordinary querying, which confirms relationships already expected - the second and third options describe verification rather than discovery.

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An operational system is which of the following?

A.A system that is used to run the business in real time and is based on historical data.
B.A system that is used to run the business in real time and is based on current data.
C.A system that is used to support decision making and is based on current data.
D.A system that is used to support decision making and is based on historical data.

Answer: B

Correct answer: A system that is used to run the business in real time and is based on current data.

An operational system records transactions as they happen, so it holds current data and is optimised for many small reads and writes. A warehouse is the opposite on both counts: historical data, optimised for large analytical queries, and used to support decisions rather than to run the business.

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A data warehouse is which of the following?

A.Can be updated by end users.
B.Contains numerous naming conventions and formats.
C.Organized around important subject areas.
D.Contains only current data.

Answer: C

Correct answer: Organized around important subject areas.

Subject orientation is the first of the defining characteristics: the warehouse is arranged around customer, product or sale rather than around the applications the data came from. The other options describe an operational system - it is the warehouse that is integrated, non-volatile and time-variant.

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A snowflake schema is which of the following types of tables?

A.Fact
B.Dimension
C.Helper
D.All of the above

Answer: D

Correct answer: All of the above

A snowflake schema is a star in which the dimension tables have themselves been normalised, so the dimensions are split into further tables. Fact, dimension and helper tables therefore all appear. The advantage is reduced redundancy; the cost is more joins and slower queries.

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The generic two-level data warehouse architecture includes which of the following?

A.At least one data mart
B.Data that can extracted from numerous internal and external sources
C.Near real-time updates
D.All of the above.

Answer: B

Correct answer: Data that can extracted from numerous internal and external sources

The two-level architecture is the simplest: operational sources feed the warehouse directly, and users query it. Data marts belong to the three-level architecture, and near real-time updating to the active warehouse - both later refinements of this basic arrangement.

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10.

Fact tables are which of the following?

A.Completely denoralized
B.Partially denoralized
C.Completely normalized
D.Partially normalized

Answer: C

Correct answer: Completely normalized

The fact table holds the measures and the foreign keys to the dimensions, and nothing that could be moved elsewhere - so it is fully normalised. It is the dimension tables that are deliberately denormalised, since flattening them reduces the joins a query must perform, at a cost in redundancy that a read-only store can afford.

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