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Practice Questions
Test your understanding with targeted questions related to the topic.
Question 1
Easy
What is the purpose of the selection operation in databases?
💡 Hint: Think of filtering data based on certain criteria.
Question 2
Easy
What happens during a Full Table Scan?
💡 Hint: Consider how you would check each item in a list.
Practice 4 more questions and get performance evaluation
Interactive Quizzes
Engage in quick quizzes to reinforce what you've learned and check your comprehension.
Question 1
What does the selection operation in relational algebra do?
- A) Filters rows from a relation based on a condition
- B) Joins two relations
- C) Projects specific columns from a relation
💡 Hint: Recall the meaning of sigma in this context.
Question 2
True or False: A Full Table Scan is more efficient when most rows will satisfy the selection condition.
- True
- False
💡 Hint: Consider the scenario of searching for a common item.
Solve 1 more question and get performance evaluation
Challenge Problems
Push your limits with challenges.
Question 1
You have a database table of products with 100,000 entries. Describe the steps and considerations for optimizing a selection query on a rarely updated column with no index available.
💡 Hint: Focus on the size and content of your data.
Question 2
A query returns 90% of a dataset. Discuss how this selectivity impacts selection strategy and resource utilization.
💡 Hint: Reflect on how selective filters enhance performance.
Challenge and get performance evaluation