Exercises for the Web Database

The initial exercise:

• Copy dbform.html, db.c and people.txt to your directory.

• DO NOT COPY dir.alp -- it is too big. Create your own text file.

• Rename db.c to be db-$sno$.c.

• Change the FNM and RFNM strings in db-$sno$.c to refer to the files in your directory.

• Compile db-$sno$.c, and copy it to the student CGI directory.

• Modify your dbform.html to refer to db-$sno$.

• Make sure that your people.txt file is writeable by everyone (e.g. chmod w+a people.txt). This allows db-$sno$ to modify it.

• Try executing db-$sno$ via dbform.html.

Some further exercises:

• Make sure you understand the working of process_pats(), num_matches(), and record_details(). They use UNIX features which are useful in a wide range of applications.

• How could the database search be speeded up? Would multiple databases help?

Hint. Since this program is complex, you may find it easier to test by using input_entries() rather than build_entries(). input_entries() allows you to enter form details (name=value pairs) from stdin so that the Web does not need to be involved.

Assignment

Extend the database application. For example, it could be improved in ONE of the following ways:

• buttons/radioboxes for something
• the input of text containing regular expressions, such as And* to match Andy, Andrew, and other strings starting with And

DOCUMENT the code and your changes at the start of db-$sno$.c.

E-mail me your copy of db-$sno$.c by 5pm, Friday 10th July.

Also, e-mail me details on how to run your copy (e.g. the address of your database search page).

My e-mail address is ad@ratree.psu.ac.th.

I will be checking the code in your directories. Do not delete anything until the end of the semester.

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