50 TOP Real Time Data Warehousing Multiple choice Questions and Answers pdf download

Read the most frequently asked 50 top Data Warehousing multiple choice questions and answers PDF for freshers and experienced

Data Warehousing Objective type Questions and Answers List


1. Which of the following features usually applies to data in a data warehouse?
A.Data are often deleted
B.Most applications consist of transactions
C.Data are rarely deleted
D.Relatively few records are processed by applications
Ans: c

2. Which of the following statement is true?
A.The data warehouse consists of data marts and operational data
B.The data warehouse is used as a source for the operational data
C.The operational data are used as a source for the data warehouse
D.All of the above
Ans: c

3. The following is true of three-tier data warehouses:
A.Once created, the data marts will keep on being updated from the data warehouse at periodic times
B.Once created, the data marts will directly receive their new data from the operational databases
C.The data marts are different groups of tables in the data warehouse
D.A data mart becomes a data warehouse when it reaches a critical size
Ans: a

4. The following technology is not well-suited for data mining:
A.Expert system technology
B.Data visualization
C.Technology limited to specific data types such as numeric data types
D.Parallel architecture
Ans: c

5. What is true of the multidimensional model?
A.It typically requires less disk storage
B.It typically requires more disk storage
C.Typical business queries requiring aggregate functions take more time
D.Increasing the size of a dimension is difficult
Ans: b

6. The value at the intersection of the row labeled “India” and the column “Savings” in Table2 should be:
A.800,000
B.300,000
C.200,000
D.300,000
Ans: a

7. We want to add the following capabilities to Table2: show the data for 3 age groups (20-39, 40-60, over 60), 3 revenue groups (less than $10,000, $10,000-$30,000, over $30,000) and add a new type of account: Money market. The total number of measures will be:
A.4
B.More than 100
C.Between 10 and 30 (boundaries includeD.
D.Between 40 and 60 (boundaries includeD.
Ans: b

8. We want to add the following capability to Table2: for each type of account in each region, also show the dollar amount besides the number of customers. This adds to Table2:
A.Another dimension
B.Other column(s)
C.Other row(s)
D.Another measure for each cell
Ans: d

9. The most common source of change data in refreshing a data warehouse is:
A.Queryable change data
B.Cooperative change data
C.Logged change data
D.Snapshot change data
Ans: d

10. Which of the following statements is not true about refreshing a data warehouse:
A.It is a process of managing timing differences between the updating of data sources and the related data warehouse objects
B.Updates to dimension tables may occur at different times than the fact table
C.The data warehouse administrator has more control over the load time lag than the valid time lag
D.None of the above
Ans: d

11. 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.
Ans: C

12. 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.
Ans: B

13. 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.
Ans: B

14. 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.
Ans: D

15. Reconciled data is which of the following?
A. Data stored in the various operational systems throughout the organization.
B. Current data intended to be the single source for all decision support systems.
C. Data stored in one operational system in the organization.
D. Data that has been selected and formatted for end-user support applications.
Ans: B

16. Transient data is which of the following?
A. Data in which changes to existing records cause the previous version of the records to be eliminated
B. Data in which changes to existing records do not cause the previous version of the records to be eliminated
C. Data that are never altered or deleted once they have been added
D. Data that are never deleted once they have been added
Ans: A

17. The extract process is which of the following?
A. Capturing all of the data contained in various operational systems
B. Capturing a subset of the data contained in various operational systems
C. Capturing all of the data contained in various decision support systems
D. Capturing a subset of the data contained in various decision support systems
Ans: B

18. 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
Ans: D

19. The load and index 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
Ans: B

20. Data transformation includes which of the following?
A. A process to change data from a detailed level to a summary level
B. A process to change data from a summary level to a detailed level
C. Joining data from one source into various sources of data
D. Separating data from one source into various sources of data
Ans: A

21. A multifield transformation does which of the following?
A. Converts data from one field into multiple fields
B. Converts data from multiple fields into one field
C. Converts data from multiple fields into multiple fields
D. All of the above
Ans: D

22. A star schema has what type of relationship between a dimension and fact table?
A. Many-to-many
B. One-to-one
C. One-to-many
D. All of the above.
Ans: C

23. Fact tables are which of the following?
A. Completely demoralized
B. Partially demoralized
C. Completely normalized
D. Partially normalized
Ans: C

24. A snowflake schema is which of the following types of tables?
A. Fact
B. Dimension
C. Helper
D. All of the above
Ans: D

25. 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
Ans: A

26. Which of the following statements does not apply to relational databases?
A. Relational databases are simple to understand
B. Tables are one of the basic components of relational databases
C. Relational databases have a strong procedural orientation
D. Relational databases have a strong mathematical foundation
Ans: C

27. In the relational database terminology, a table is synonymous with:
A. A column
B. A row
C. An attribute
D. A relation
Ans: D

28. A null value indicates:
A. A numeric value with value 0
B. The absence of a value
C. A very small value
D. An erroneous value
Ans: B
29. When the referential integrity rule is enforced, which one is usually not a valid action in response to the deletion of a row that contains a primary key value referenced elsewhere?
A. Do not allow the deletion
B. Accept the deletion without any other action
C. Delete the related rows
D. Set the foreign keys of related rows to null
Ans: B
30. When an equi-join is performed on a table of N rows and a table of M rows, the resulting table has the following number of rows:
A. M
B. N
C. The smaller of M or N
D. A number in the range 0 to M*N
Ans: D
31. The Union of a table of N rows and of a table of M rows (M<=N) has the following number of rows: A. M+N B. A number in the range N to M+N C. N D. A number in the range 0 to M Ans: B 32. The following pair of tables is union compatible: A. Dept1, Dept4 B. Dept1, Dept3 C. Dept3, Dept4 D. All of the above Ans: A 33. A data mart is designed to optimize the performance for well-defined and predicable uses. A. True B. False Ans: A 34. Successful data warehousing requires that a formal program in total quality management (TQM) be implemented. A. True B. False Ans: A 35. Data in operational systems are typically fragmented and inconsistent. A. True B. False Ans: A 36. Most operational systems are based on the use of transient data. A. True B. False Ans: A 37. Independent data marts are often created because an organization focuses on a series of short-term business objectives. A. True B. False Ans: A 38. Joining is the process of partitioning data according to predefined criteria. A. True B. False Ans: B 39. The role of the ETL process is to identify erroneous data and to fix them. A. True B. False Ans: B 40. Data in the data warehouse are loaded and refreshed from operational systems. A. True B. False Ans: A 41. Star schema is suited to online transaction processing, and therefore is generally used in operational systems, operational data stores, or an EDW. A. True B. False Ans: B 42. Periodic data are data that are physically altered once added to the store. A. True B. False Ans: B 43. Both status data and event data can be stored in a database. A. True B. False Ans: A 44. Static extract is used for ongoing warehouse maintenance. A. True B. False Ans: B 45. Data scrubbing can help upgrade data quality; it is not a long-term solution to the data quality problem. A. True B. False Ans: A 46. Every key used to join the fact table with a dimensional table should be a surrogate key. A. True B. False Ans: A 47. Derived data are detailed, current data intended to be the single, authoritative source for all decision support applications. A. True B. False Ans: B 48. Because they should not contain SQL manipulation statements, what kind of trigger is typically used to enforce complex integrity constraints? A. AFTER ROW triggers B. BEFORE ROW triggers C. INSTEAD OF triggers D. None of the above Ans: B 49. Which of the following is not a common cursor attribute? A.%IsOpen B.%IsNotOpen C.%Found D.%NotFound Ans: B 50. The INTO clause of the SELECT statement: A. Can be used only when the SELECT statement returns at most one row. B. Does not generate an exception if no rows are returned. C. Is not a valid clause in PL/SQL. D. None of the above. Ans: A

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