University:
California State University, Northridge
Course:
COMP 440 | Database Design
Academic year:

2024
Views:

277

Pages:

13
Author:

Samuel K.

Quiz: The Relational Database Model A+ Due Sep 20 at 11:59pm Points 15 Questions 15 Time Limit 30 Minutes Allowed Attempts 2 Take the Quiz Again Attempt History Attempt Time Score LATEST Attempt 1 19 minutes 13 out of 15 Question 1 1/1 pts To be considered minimally relational, the DBMS must support the key relational operators PROJECT, and JOIN. INTERSECT SELECT Correct. The DBMS must support the SELECT, PROJECT, and JOIN operators to be considered relational. UNION DIFFERENCE Question 2 1/1 pts also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition. INTERSECT SELECT Correct. SELECT is used to select a subset of rows given by a condition. UNION DIFFERENCE Question 13 1/1 pts Which of the following options is more adequate for a primary key in a table of employees? home phone number a combination of name and surname name and date of birth employee social security number Correct. Since the primary key must uniquely identify an entity of the table, in this case an employee, the most adequate is the social security number. Since there can't be, even by coincidence, two employees with the same social security number. Feedback: Question 14 1/1 pts Which of the following is a reason to use indices in a database? Avoid redundancy between tables. Create unique indices related to non unique attributes. Recreate M:N relations as two 1:N relations Retrieve data ordered by a specific attribute. Correct. Aside from retrieving data faster, indices can be used for other purposes like retrieving data in an ordered way by a specific attribute. Question 15 1/1 pts Character data can contain any character or symbol intended for mathematical manipulation. True False Correct. Character data is also known as string data or text. The content is not intended for mathematical manipulation. Question 3 0/1 pts From the table's user, the table contains related entities data unrelated entities entity sets Incorrect. Exactly each table contains entity occurrences that are related by their attributes.