13.3
Consider the relations section and takes. Give an example instance of these two relations, with three sections, each of which has five students. Give a file structure of these relations that use multitable clustering.
The relation section with three tuples is as follows:
course_id | sec_id | semester | year | building | room_number | time_slot_id
-----------+--------+----------+------+-----------+-------------+--------------
747 | 1 | Spring | 2004 | Gates | 314 | K
362 | 1 | Fall | 2005 | Lamberton | 143 | I
192 | 1 | Fall | 2002 | Polya | 808 | B
(3 rows)The relation takes with five students for each section is as follows:
id | course_id | sec_id | semester | year | grade
-------+-----------+--------+----------+------+-------
74016 | 747 | 1 | Spring | 2004 | A-
1110 | 747 | 1 | Spring | 2004 | B
90779 | 747 | 1 | Spring | 2004 | A-
65987 | 747 | 1 | Spring | 2004 | B
84432 | 747 | 1 | Spring | 2004 | B+
18709 | 362 | 1 | Fall | 2005 | A+
35362 | 362 | 1 | Fall | 2005 | C-
81896 | 362 | 1 | Fall | 2005 | B+
80057 | 362 | 1 | Fall | 2005 | A+
31341 | 362 | 1 | Fall | 2005 | B-
97042 | 192 | 1 | Fall | 2002 | A-
56598 | 192 | 1 | Fall | 2002 | A+
32376 | 192 | 1 | Fall | 2002 | A+
50039 | 192 | 1 | Fall | 2002 | A-
14182 | 192 | 1 | Fall | 2002 | B+
(15 rows)The multitable clustering for the above two instances can be taken as:
747 | 1 | Spring | 2004 | Gates | 314 | K
74016 | 747 | 1 | Spring | 2004 | A-
1110 | 747 | 1 | Spring | 2004 | B
90779 | 747 | 1 | Spring | 2004 | A-
65987 | 747 | 1 | Spring | 2004 | B
84432 | 747 | 1 | Spring | 2004 | B+
362 | 1 | Fall | 2005 | Lamberton | 143 | I
18709 | 362 | 1 | Fall | 2005 | A+
35362 | 362 | 1 | Fall | 2005 | C-
81896 | 362 | 1 | Fall | 2005 | B+
80057 | 362 | 1 | Fall | 2005 | A+
31341 | 362 | 1 | Fall | 2005 | B-
192 | 1 | Fall | 2002 | Polya | 808 | B
97042 | 192 | 1 | Fall | 2002 | A-
56598 | 192 | 1 | Fall | 2002 | A+
32376 | 192 | 1 | Fall | 2002 | A+
50039 | 192 | 1 | Fall | 2002 | A-
14182 | 192 | 1 | Fall | 2002 | B+