Specifications

If we pass in an array containing the book data, the form will be rendered in edit mode and

will fill in the fields with the existing data:

<input type=text name=price

value=”<?=$edit?$book[“price”]:””; ?>”>

We even get a different submit button. In fact, for the edit form we get two—one to update the

book, and one to delete it. These call the scripts edit_book.php and delete_book.php, which

update the database accordingly.

The category versions of these scripts work in much the same way except for one thing. When

an administrator tries to delete a category, it will not be deleted if any books are still in it.

(This is checked with a database query.) This avoids any problems we might get with deletion

anomalies. We discussed these in Chapter 7, “Designing Your Web Database.” In this case, if a

category was deleted that still had books in it, these books would become orphans. We

wouldn’t know what category they were in, and we would have no way of navigating to them!

That’s the overview of the administration interface. For more details, refer to the code—it’s all

on the CD-ROM.

Extending the Project

We have built a fairly simple shopping cart system. There are many additions and enhance-

ments we could make:

• In a real online store, you would need to build some kind of order tracking and fulfill-

ment system—at the moment, there’s no way to see the orders that have been placed.

• Customers want to be able to check the progress of their orders without having to contact

you. We feel that it is important that a customer does not have to log in to browse.

However, providing existing customers a way to authenticate themselves gives them the

ability to see past orders, and gives you the ability to tie behaviors together into a profile.

• At present, the images for books have to be FTPed to the image directory and given the

correct name. You could add file upload to the book insertion page to make this easier.

• You could add user login, personalization, and book recommendations; online reviews;

affiliate programs; stock level checking; and so on. The possibilities are endless.

Using an Existing System

If you want to get a highly featured shopping cart up and running quickly, you might want to

try using an existing shopping cart system. One well known Open Source cart implemented in

PHP is FishCartSQL, available from

http://www.fishcart.org/

Building Practical PHP and MySQL Projects

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