MCQs on Advanced Data Modeling | Qlikview MCQ Questions
Master advanced data modeling concepts in QlikView with these 30 multiple-choice questions. Topics covered include Star and Snowflake Schemas, Circular References, Joins, Concatenations, and Performance Optimization for efficient modeling.
Understanding Star and Snowflake Schemas
1. In a Star Schema, which of the following is true about the fact table?
A) It is placed in the center and connected to dimension tables
B) It is stored in separate databases
C) It contains minimal data
D) It stores multiple fact types
2. A Snowflake Schema is different from a Star Schema because:
A) It uses more fact tables
B) It normalizes the dimension tables
C) It has fewer relationships
D) It stores data in an unstructured format
3. What is a primary advantage of using a Star Schema?
A) It requires complex joins
B) It is easy to query and understand
C) It normalizes data
D) It has fewer tables
4. Which of the following is an advantage of a Snowflake Schema over a Star Schema?
A) It reduces data redundancy
B) It is easier to query
C) It provides faster data retrieval
D) It uses fewer tables
5. Which schema type is preferred for reporting and business intelligence due to simplicity?
A) Star Schema
B) Snowflake Schema
C) Hybrid Schema
D) Network Schema
Circular References and Synthetic Keys
6. Circular references in QlikView occur when:
A) There is more than one fact table in the model
B) There are no joins between tables
C) Tables reference each other in a loop
D) Synthetic keys are generated
7. What is a synthetic key in QlikView?
A) A unique key created automatically by the system
B) A composite key generated when multiple fields are used to create a primary key
C) A manually defined key
D) A foreign key used for joining tables
8. How can circular references be resolved in QlikView?
A) By removing all links between tables
B) By creating additional synthetic keys
C) By using the “Drop Fields” function
D) By restructuring the data model and eliminating the loops
9. What is the consequence of having synthetic keys in a QlikView data model?
A) It simplifies relationships
B) It improves the performance of the model
C) It can lead to incorrect results and slow performance
D) It makes the data model easier to understand
10. Which function can be used in QlikView to avoid synthetic keys and circular references?
A) Set Analysis
B) Join Function
C) LinkTable
D) AutoNumber()
Using Joins and Concatenations
11. In QlikView, what is the purpose of using a Join?
A) To load data from external files
B) To combine multiple tables based on common fields
C) To create synthetic keys
D) To remove redundant data
12. What type of Join combines records from two tables when they have matching keys?
A) Left Join
B) Inner Join
C) Right Join
D) Outer Join
13. What is the result of using a Left Join in QlikView?
A) Only matching rows from both tables
B) All rows from the right table and matching rows from the left table
C) All rows from the left table, with matching rows from the right table
D) No rows are combined
14. What does Concatenation mean in QlikView?
A) Merging rows from different tables into one unified table
B) Creating a new field by combining multiple fields
C) Joining tables based on common keys
D) Creating a new synthetic key
15. Which of the following is true when using the automatic concatenation feature in QlikView?
A) It merges tables only if they have matching field names
B) It concatenates tables with different field names
C) It requires manual specification of fields
D) It creates new tables from scratch
Optimizing Data Models for Performance
16. To optimize QlikView data models, it is important to:
A) Use as many synthetic keys as possible
B) Minimize the number of data sources
C) Reduce the number of tables and relationships
D) Avoid using joins
17. What impact does using too many concatenated tables have on performance?
A) It enhances the performance
B) It increases data redundancy
C) It leads to slower data load times and complex queries
D) It simplifies the model
18. How can QlikView data models be optimized for faster queries?
A) By using complex joins for multiple tables
B) By reducing the number of fields loaded into memory
C) By using synthetic keys to combine tables
D) By increasing the number of fact tables
19. Which method can be used to improve QlikView’s memory performance?
A) Use only a single data source
B) Apply Data Compression techniques
C) Load all data into a single table
D) Load data in a non-normalized form
20. Which of the following strategies can reduce the load time of a QlikView application?
A) Use the “Preload” function
B) Optimize the data model by removing unnecessary fields
C) Increase the number of tables in the model
D) Use multiple data connections
Mixed Topics and Practical Scenarios
21. What does the term “Concatenation” refer to when combining tables?
A) Aligning tables based on column names
B) Merging tables with similar columns into one table
C) Performing a full outer join
D) Filtering rows in a table
22. In QlikView, what is the primary advantage of using a Star Schema over a Snowflake Schema?
A) It reduces the number of tables
B) It normalizes dimension data
C) It simplifies the data structure for reporting
D) It is easier to maintain
23. What happens when two tables in QlikView share no common field but are joined using a common key?
A) A Cartesian Join occurs
B) A circular reference is created
C) The tables will concatenate automatically
D) A synthetic key is created
24. When optimizing a data model in QlikView, why should unnecessary fields be removed?
A) To prevent circular references
B) To reduce memory usage and improve performance
C) To increase data redundancy
D) To ensure synthetic keys are created
25. What is the best practice for handling large datasets in QlikView?
A) Use multiple smaller models
B) Load data from external databases only
C) Use complex nested queries
D) Use data compression and optimized indexing
26. Which of the following is a key characteristic of a Snowflake Schema?
A) Large fact tables
B) Highly normalized dimension tables
C) Simple relationship structure
D) Unstructured data
27. In QlikView, which type of join should be used to retrieve only matching records from two tables?
A) Left Join
B) Inner Join
C) Outer Join
D) Right Join
28. What is the result of using a “Full Outer Join” in QlikView?
A) It combines all rows from both tables
B) It combines only rows with matching keys
C) It adds null values for unmatched rows
D) It filters out rows with no match
29. What is a common issue when concatenating tables that do not have identical field names?
A) It results in a circular reference
B) It leads to synthetic keys
C) It creates multiple fact tables
D) It leads to incorrect relationships
30. What should be done when circular references are detected in QlikView?
A) Manually remove tables from the data model
B) Use AutoNumber() to generate unique keys
C) Break the loop by restructuring the model
D) Add more fact tables
Answers
| QNo | Answer (Option with the text) |
|---|---|
| 1 | A) It is placed in the center and connected to dimension tables |
| 2 | B) It normalizes the dimension tables |
| 3 | B) It is easy to query and understand |
| 4 | A) It reduces data redundancy |
| 5 | A) Star Schema |
| 6 | C) Tables reference each other in a loop |
| 7 | B) A composite key generated when multiple fields are used to create a primary key |
| 8 | D) By restructuring the data model and eliminating the loops |
| 9 | C) It can lead to incorrect results and slow performance |
| 10 | C) LinkTable |
| 11 | B) To combine multiple tables based on common fields |
| 12 | B) Inner Join |
| 13 | C) All rows from the left table, with matching rows from the right table |
| 14 | A) Merging rows from different tables into one unified table |
| 15 | B) It concatenates tables with different field names |
| 16 | C) Reduce the number of tables and relationships |
| 17 | C) It leads to slower data load times and complex queries |
| 18 | B) By reducing the number of fields loaded into memory |
| 19 | B) Apply Data Compression techniques |
| 20 | B) Optimize the data model by removing unnecessary fields |
| 21 | B) Merging tables with similar columns into one table |
| 22 | C) It simplifies the data structure for reporting |
| 23 | A) A Cartesian Join occurs |
| 24 | B) To reduce memory usage and improve performance |
| 25 | D) Use data compression and optimized indexing |
| 26 | B) Highly normalized dimension tables |
| 27 | B) Inner Join |
| 28 | A) It combines all rows from both tables |
| 29 | B) It leads to synthetic keys |
| 30 | C) Break the loop by restructuring the model |