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Module 8: Building Fast-Performing Database Models.

Building Fast-Performing Database Models.

1. Which of these apply to OLTP databases?

A. Large Transaction

B. High concurrency

C. Frequent servicing opportunities

D. Real-time response to end-users

Answer: B

2. Which of these apply to data warehouse databases?

A. Lots of users

B. High concurrency

C. Very large database

D. High Granularity

Answer: C

3. Which aspect of a query affects performance most profoundly? Select the most appropriate answer.

A. WHERE clause filtering

B. Sorting with the order by clause

C. Aggregating with the GROUP BY clause

D. The number of tables in join queries

E. The number of fields in join queries

Answer: D

4. Assume that there 1000000 records in a table. One record has empno=100. empno as the primary key. Which is the fastest query?

A. SELECT * from emp where empno!=100;

B. SELECT * from emp where empno=100;

C. SELECT * from emp where empno is NULL;

D. SELECT * from emp where empno>100;

Answer: B

5. Which databases models does Factors Tuning affect?




D. None

Answer: A, B, C

6. Application caching is where data can be stored in the memory of a client computer.

A. True

B. False

C. None

Answer: A

7. What is true for views?

A. Views are database objects and logical overlays

B. Views are database objects and physical overlays

C. Views hold data 

D. A & B

Answer: A

8. When should not be created an index?

A. A table small number of field’s

B. Small static data tables

C. A table large number of field’s

D. A & B

Answer: D

9. Which data are changes all the are called-

A. Static data

B. Dynamic data

C. Transactional data   

D. All of the above

Answer: B, C

10. What is unique index?

A. A unique index is allowing only a single value in a table.

B. A unique index is allowing multiple values in a table.

C. A unique index is allowing duplicate value in a table.

D. None

Answer: A

11. An auto counter is a specific database object used to count –

A. Char values

B. Date values

C. Integer values

D. Decimal values

Answer: C

12. What are basic rules when attempting to tune SQL code joins?

A. Apply largest filters first

B. Use indexes

C. Nested Subquery semi-joins 

D. Only a

Answer: A, B, C

13. The most important factor for performance tuning joins is minimizing the number

A. Of tables

B. of records

C. of rows

D. of fields

Answer: A

14. What are true about joins?

A. An inner join is an intersection between two tables.

B. A self-join is a special type of intersection where records on multiple heretical levels, stored in a single table.

C. A cross join is Cartesian product

D. None

Answer: A, B, C

15. The where clause can be used to-

A. Include wanted records

B. Exclude unwanted records

C. Filter records

D. None of above

Answer: A, B, C

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