Ben Bartlett
10/5/00
V. 2

Original Changes:
=================
    The change I made to WebDB was to add a table which displays the times
of the classes a student is registering for. It appears in the
registration card window. It consists of a representation of half an hour
time blocks for each day of the school week. If a class which the
student has added to his or her card meets during that half an hour, it
colors the time block black. If more than one class meets during that half
an hour, it colors the block red. That way, it is easy for students who
are registering for classes to see when the classes they have signed up
for conflict with one another.
    In order to implement this table, I had to make changes in two
modules, DATA_ACCESS.pm and reg_card.cgi. I was hoping that it would be
possible to reuse a function in DATA_ACCESS.pm, thinking that perhaps
there was a specific function which did nothing but displayed the table,
but sadly, this was not the case. Instead, there was a very specific
function, current_schedule, which looked in the database for a person's
current schedule and displayed both the table and specific information
about the person's current classes. I thought this was a rather large
oversight in design, as it would've been better to have one function look
up the current schedule in the database, and then send that information to
two other functions, one which would display the class times table, and
one which would display the specific information on the classes. However,
as this was not the case, I simply copied current_schedule into a function
called registration_schedule, then altered it so that it would get the
information for the courses on the student's registration card. I also
altered the function so that it would only print out the table of class
times, and so that it would color conflicting class times red. For
reg_card.cgi, all I had to do was populate the parameters to send to the
registration_schedule function (I copied much of this from person.cgi,
which calls current_schedule), and then called
registration_schedule. Thus, the vast majority of the work was actually
done in the DATA_ACCESS.pm module, rather than in the reg_card.cgi module.
    This project took a great deal longer than the estimation for it
suggested. It took me at least 5 hours to design my solution. Much of this
was spent just trying to understand the data model for WebDB. Then it took
me another 5 hours to code and debug my solution. I think this is due to
the fact that the learning curve was high; not only was I unfamiliar with
WebDB, but I also know very little about HTML, and nothing at all about
JavaScript or CGI. It did help that I was familiar with Perl, however. I
think if I had the time to sit down and do this right, however, I'd go
back into DATA_ACCESS.pm and split up those functions the way I think they
ought to be split up. It would improve their reusability remarkably. I
hate having two functions which do virtually the same thing. But, as it
is, I have a workable solution, and I've managed to do it within the time
required (albeit the adjusted time required), and so I will have to live
with it.

Summary:
========
    Modules Modified:
        - DATA_ACCESS.pm
        - reg_card.cgi
    Time:
        Design: 5 hours
        Code: 3 hours
        Debug: 2 hours

The Changes:
============
    Last time, I noticed that the functions were not very well
modularized. I set about fixing that. I split current_schedule into 3
functions: get_current_schedule, which gets the data from the database,
print_blocks, which prints a chart of class times, and print_schedule,
which prints the schedule description. I then altered my original 
function, registration_schedule so that it would return ths same type of
information as get_current_schedule, only for whatever classes were on the
person's registration card, instead of what classes that person is
currently taking. These four functions are located in DATA_ACCESS.pm.
    In addition, I altered person.cgi and reg_card.cgi to use these new
functions in place of the old ones. It is now possible to reuse both the
data access functions, and the data display functions. I am much happier
with this solution, as it will make any future changes of this sort much
simpler.

Summary:
========
    Modules Modified:
        - DATA_ACCESS.pm
        - person.cgi
        - reg_card.cgi
    Time:
        Design: 15 minutes
        Coding: 1 hour
        Debugging: 30 minutes