2.5
What is the result of first performing the Cartesian product of student and advisor, and then performing a selection operation on the result with the predicate s_id = ID? (Using the symbolic notation of relational algebra, this query can be written as \(\sigma_{s\_id = ID}(student \times advisor)\).)
The result attributes include all attribute values of student followed by all attributes of advisor. The tuples in the result are as follows: For each student who has an advisor, the result has a row containing the student’s attributes, followed by s_id attribute identical to the student’s ID attribute, followed by the i_id attribute containing the ID of the students advisor.
Students who do not have an advisor will not appear in the result. A student who has more than one advisor will appear a corresponding number of times in the result.