[NH] Re: Any ideas on a shopping cart?
- I do not know of any free tutorials, although they likely exist.
Here is a quick overview of how the process works. Realize it is MUCH
more involved then merely creating a page in HTML and uploading it.
Also, for security reasons, many ISP's will require that they do all the
necessary programming themselves. At a minimum, they will need to
inspect all the CGI scripts, to be sure they do not contain malicious or
erroneous code that could mess up their servers, or other customers' web
Some sort of CGI is essential. They are usually written in Perl.
Normally, such a web page is connected to a SQL database. 'MySQL' is a
_very_ good SQL server if the web server is on any sort of Unix platform.
And MySQL is also free. The database stores information about available
products, user information and account history, the contents of the
user's shopping cart, and information needed to track the cookies used by
the web browser.
The SQL database is important because CGI scripts remember nothing.
Every time the users clicks on a link, the CGI script tied to that page
has to "relearn" everything about that user. This is usually done by
using cookies and an SQL database. The user's web browser sends the
cookie to the web server every time the user goes back to the page that
issued it. The cookie contains a number that uniquely identifies the
user. Then the CGI scripts uses that number as a key, and asks the SQL
server to remind it everything else about that user - name, contents of
shopping cart, etc. Then the CGI updates the SQL database with whatever
change the user made (such as adding a new item to the cart. Then it
creates, on the fly, an HTML page customized for this user, and sends it
to the web browser to be displayed. After that point the CGI program
terminates. When the user clicks another link on the page, this whole
An alternative approach (which is growing in popularity) is to use an
IMBEDDED scripting language like PHP. Still, one needs an SQL database
for the actual data storage.
I warn you that setting up the database requires comand-line access to
the server, and the permission of the server's owner. Easy if the server
is on one's own machine - but for most of us, it is not. If one is using
an ISP's web server, one will need to work out a contract with them. One
will likely spend a significant amount of money just to have their ISP
set things up, and also have pay ongoing fees for the database hosting.
(Which is rarely, if ever, included with "basic" web hosting.)
Wayne M. VanWeerthuizen
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