How to make a form verify from a database

Question

I need to create a page that will have a person enter their
membership number and if they are in our database they will receive
a 10% discount on their items ordered.
I set up a database and my webpage with a textfield for them
to enter their member number. But now sure how or what needs to be
done to the webpage to connect to the database and return a true
statement so the person gets a discount if they are a member.
Also, is there a script that would calculate a 10% discount?

Answer 1

Ajax (Javascript) would have an edge over PHP in regards to responsiveness. The best solution might combine all three methods (PHP, Javascript, HTML).
Are the responses going to be stored in a database? If so then you can also use the database to store the questions, complete with form fields.
One big difference between javascript and PHP is that PHP does nothing until you either open a new page or hit submit, and then it runs in a linear fashion until it reaches the end of the script. Javascript, on the other hand, can respond to other "events" that take place, such as when the user clicks away from a form field. With the advent of html5, HTML now has a little of the responsiveness of javascript.
PHP is the tool you use for processing form data and interacting with the database, if each form response is followed by a complete PHP processing cycle, the form will seem sluggish to the user. There are two solutions to this:
Have the user respond to a group of questions, then hit submit. The occasional lag for page reload won't bother the user.
Use AJAX to interact with the PHP form processing behind the scenes.
So yes, you can have one page that responds and changes depending on user input. PHP, javascript and HTML5/CSS3 can all be part of this. The specific way you build your solution will depend on your specific form progress and what technologies you are most comfortable with. For instance, my strong case is PHP, so I let it do as much of the work as possible, but I know coders who do much of what I would do in PHP with javascript, because that's what they are most comfortable using.
Any resources on how I might be able to do this via PHP?
PHP Solutions second edition by David Powers
Programming PHP by Lerdorf, Tatrow and MacIntypre