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ASSIGNMENT 3 – 601.315/415/615 – Databases

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ASSIGNMENT 3 – 601.315/415/615 – Databases

The Assignment:
The goal of Assignment 3 is to implement a number of MySQL stored procedures that
function on a course grade database similar to database that would be used in a class
like 601.315/415. In addition, you will implement simple web interfaces that can access a
database.
The database itself has been defined for you, and can be found in the following SQL file
on dbase: /home/cs415/grades.sql. Your task is to write the MySQL stored procedures
that access and manipulate this database, as well as HTML forms that that interface with
the database, and possibly with the MySQL procedures you created The specifications that
these procedures/forms must satisfy are found below.
Format of the Database:
The 601.315/415/615 grade database is a simple flat table of the following form:
SSN LName FName Section HW1 HW2a HW2b Midterm HW3 FExam
9176 Epp Eric 415 99 79 31 99 119 199
5992 Lin Linda 415 98 71 29 83 105 171
3774 Adams Abigail 315 85 63 27 88 112 180
1212 Osborne Danny 315 29 31 12 66 61 106
4198 Wilson Amanda 315 84 73 27 87 115 172
1006 Nielsen Bridget 415 93 76 28 95 111 184
8211 Clinton Chelsea 415 100 80 32 100 120 200
1180 Quayle Jonathan 315 50 40 16 55 68 181
0001 TOTAL POINTS 415 100 80 32 100 120 200
0002 WEIGHT OFSCORE 415 .10 .10 .05 .25 .10 .40
This relation (called rawscores) contains the raw scores on individual assignments, along
with the names and section numbers of each student and the last 4 digits of their social
security number (which is assumed to be unique and serves as the primary key).
The problem has been made more complex in that the total points possible for each
assignment is stored as part of the same table, with the special SSN 0001. Unlike in the
real 601.315/415/615, the total points possible for 315 and 415/615 are the same. Also, the
weight to be given to each assignment (as a percentage summing to 1) is given under the
special SSN 0002.
Note that in order to simplify your MySQL coding, you are allowed to create views
called TotalPoints and Weights that have the same attribute names as in the full table,
but contain only 1 special tuple (0001 and 0002 respectively) with just the total points or
weights. This can avoid the necessity to extract these values in an embedded query.
Finally, there is a single additional relation called Passwords with a single attribute
called CurPasswords. Although the relation normally only has one tuple (the single current
password), it may potentially have multiple tuples, all of which are valid current passwords.
Passwords:
CurPasswords
OpenSesame
GuessMe
ImTheTA
What To Do:
You should write MySQL procedures and HTML interfaces that provide the following
functionality:
(a) Print a single student’s raw scores:
You should write a MySQL stored procedure ShowRawScores that takes a single argument (SSN) and prints out the tuple of values in the rawscores table that correspond
to that SSN. Note that the only security mechanism here is that the user must know
the SSN to have access to a student’s scores.
(b) Print a single student’s percentage scores and weighted average:
You should write a MySQL stored procedure called ShowPercentages that takes a
single argument (SSN) and prints out the tuple of values in the rawscores table that
correspond to that SSN, but where each score has been divided by the total points
for that assignment and multiplied by 100, yielding a percentage value.
This procedure should then compute the weighted average of all the scores for the
student, using the relative weights given in the tuple with SSN = 0002, as shown
above. For example, this average would be computed in a formula like:
(score.hw1 * (1/totpts.hw1) * weight.hw1 +
score.hw2a * (1/totpts.hw2a) * weight.hw2a +
score.hw2b * (1/totpts.hw2b) * weight.hw2b +
score.midterm * (1/totpts.midterm) * weight.midterm + …..)
Note that you can simplify this formula by creating additional views such as WtdPts,
which contains the precomputed products of (1/totpts.hwi) * weight.hwi.
The output for this weighted average should be a separate SELECT statement stating
“The cumulative course average for FName LName is CumAvg”, where FName and
LName correspond to the provided SSN, and CumAvg is the value computed as shown
above.
(c) Print a full table of the raw class scores
You should write a MySQL procedure AllRawScores that prints out the basic full
rawscores table, excluding the totalpoints and weight tuples. You should sort by
section number first, last name and then first name.
The procedure should take a single string argument called password, which is a system access password. This procedure should first check that the password provided
appears in the table Passwords to prevent unauthorized access. Needless to say, this
check should occur before printing the table. If the password isn’t in the table of
current passwords, the procedure should instead print an appropriate error message.
(d) Print a full table of the percentage scores and weighted total
You should write a MySQL procedure AllPercentages that performs a similar task
to ShowPercentages in computing the percentage values for each assignment and a
weighted average of them. However, AllPercentages should print one such line for
every student, sorted by the section (315/415/615) first and the weighted average
second.
AllPercentages should take and handle a single password argument just like AllRawScores.
(e) Compute aggregate statistics on the tables (601.415/615 only)
You should write a MySQL procedure Stats that is a modification of AllPercentages
and prints the following additional aggregate information below the primary table:
the mean of the percentage scores, the minimum percentage scores, the maximum
percentage scores, and the standard deviation of the percentage scores. Those statistics should be calculated for each individual assignment, as well as for the cumulative
average. Each of those four statistics (mean, min, max, and std. dev.) should get its
own one-line table. Each of these four additional tables should have the assignment attribute labels (hw1, hw2a, etc) acting as headers, in addition to an extra header titled
“Statistic” whose value in the sole entry is one of “Mean”/“Minimum”/“Maximum”
and “Std. Dev.”
For some extra credit, these aggregate statistics should be computed separately for
the two sections (315 and 415), in which case you are also required to separate the
original table into two tables, one for each section.
(f) Write a procedure to change student scores (601.415/615 only)
You should write a MySQL procedure ChangeScores that takes 4 arguments (password, SSN, AssignmentName and NewScore). It should verify the password as before,
and then replace the current score for the assignment called ’AssignmentName’ for
the given SSN with the NewScore. Doing this in a general way can be tricky, but
you are allowed to use brute force (i.e. a long code segment testing for each of the
assignment name labels.) As before, the password should be verified before replacing
the score.
In addition to actually changing the score, the procedure should print out the full raw
score tuple for that student before and after the change. testing for each condition).
(g) Write simple PHP/MySQL Interfaces for Updating a Student’s Scores and
for Displaying Results (everyone)
Details of this task and examples will be given and demonstrated in class and communicated via an e-mail to the class. Notes:
Notes:
• In all of your procedures, you should guard for errors (e.g. invalid SSN or password)
and should also print appropriate error messages to the user. Improper handling of
errors will be penalized.
• All those procedures should be written in a text editor and formatted clearly in a
single text file called DavidYarowsky HW3.sql, where you you use your own first and
last names instead.
• This assignment is actually shorter than it might appear to you. A considerable
percentage of the code for procedure declarations can be shared between the different
parts of the assignment.
What To Hand In:
You should write all your procedures in a text editor, formatted clearly. Submit this file
where the procedures using gradescope, equivalent to HW2. as in HW2.
In addition, you are required to submit any files created for item (g) above using the
HW2 gradescope instructions.

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