Revision Questions for Week 3 and 4: use the
Student Notes book to answer these questions. The answers will
be discussed briefly during the lecture.
Which of the following is NOT an ER diagram connection trap?
A many-to-one relationship between Ingredients and Meals and a
many-to-one relationship between Dishes and Meals constitutes
a possible fan trap because the pathway between Ingredients
and Dishes is ambiguous.
The fan trap can be resolved by changing the many-to-one relationship
between Ingredients and Meals into a
many-to-one relationship between Ingredients and Dishes.
A Chasm trap can occur if ... (choose one)
some relationships are optional
Which of the following is NOT part of Enhanced ER Models (EER)?
Which of the following is a relationship, relationship type or relation?
Bus-Driver: relationship type
Bus 14 - Driver John Smith: relationship
The database table that holds the data about buses and drivers: relation
Which of the following is NOT true?
1:m relationships are mapped by taking the primary key from the
'many end' and adding it to the 'one end' as a foreign key.
Which of the following may include rows that failed the JOIN
condition because of NULL values?
What are the two aliases in "SELECT name, address from
student undergraduate, student postgraduate"?
undergraduate and postgraduate.
Which of the rows in the following table is not an equivalence (i.e. produces
the same result if used in SQL)?
SELECT * FROM department WHERE ...
|"depno > ANY (1,2,3)" || "depno = 1 AND depno =2
AND depno =3" |
Which of the following is correct?
None of the answers is correct. A correct answer would be:
CREATE table student (name varchar(20), dob date);