Web Database Applications with PHP, and MySQL

Case Study: Adding Sessions to the Winestore

In this section we use sessions to improve the user interaction with the client entry <form> developed in Chapter 6. The improvements focus on the interaction when the <form> is submitted and fields don’t validate. We modify the scripts to:

• Display error messages on the client entry <form>

• Use session variables to pass back the submitted fields to the <form> generation script, saving the user rekeying all the data to correct the errors

Improving the Client Entry <form>

The client entry <form>, generated by the script shown in Example 6-7, collects client fields to either create a new client or edit the details of an existing client. The script shown in Example 6-8 performs the server-side validation of the client <form> data, and updates or inserts a row in the customer table if there are no errors.

If the validation fails, the script shown in Example 6-8 generates a page to display the errors to the user, and the user then follows a hypertext link back to the client entry <form> to reenter the fields. The solution provided by Example 6-7 and Example 6-8 suffers three problems:

• The user is forced to reenter the entire client entry <form> from scratch when an error is encountered during validation

• The errors that are encountered during validation are displayed by Example 6-8 and not the entry <form> where they would be useful

• The error page generated by Example 6-8 isn’t safe from the reload problem described in Chapter 6

In this section ...