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| Advanced Relational Database Modeling |
1. Which of the following is true about de-normalization?
A. De-normalization is often the opposite way of normalization.
B. De-normalizing BCNF leads to poor performance.
C. After de-normalizing 4th normal form, the remaining problem with multi-valued field is solved by collection arrays.
D. None of above is true
Answer: A
2. When does the de-normalization trick of copying field between tables is applied?
A. If there are active and inactive data.
B. If the tables are not directly related to each other.
C. If hot block problem appears
D. None of above.
Answer: B
3. Which of the following is true?
A. An abstract class is a class inhering every thing from parent class, allowing local overriding changes.
B. A specialized class is a class inhering every thing from parent class, allowing local overriding changes.
C. A method is equivalent to a relational database stored procedure; it executes on the data contents of all other objects.
D. All of above is true
Answer: D
4. We can use cluster to
A. Separate active fields
B. To copy fields between to tables
C. To make summery fields in parent table
D. We do no use cluster for de-normalization
Answer: B
5. Which type of database can consume large portion of RAM by transferring data between disk and memory.
A. OLTP
B. Client server
C. Ware house
Answer: C
6. It is only best to add or remove in a data ware house, because
A. Changing existing data warehouse table records can be extremely inefficient because of the inefficient size of RAM
B. Changing existing data warehouse table records can be extremely inefficient because of the inefficient size of Hard Disk
C. Changing existing data warehouse table records needs a change in the database design
D. None of the above statements are true.
Answer: A, B
7. What is true about snowflake schema (choose two)
A. A snowflake schema is a normalized star schema
B. A snowflake schema is a normalized fact table
C. The problem with snowflake schema isn’t too many tables but too many layers
D. The problem with snowflake schema isn’t too many layers but too many tables
Answer: A, C
8. Dimension tables must be built before the fact table
A. True
B. False
Answer: A
9. What kind of use of database requires a precise, accurate and instant picture of data in database?
A. Data storage use
B. Operational use
C. Decision support use
D. Design use
Answer: B
10. Fact table remains relatively constant in record numbers.
A. True
B. False
Answer: B
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