dynamic site were content changes

[bumpn]

how do i go about creating a site like amazon,ebay and such were the content can change. I know using a data base and sql and php but I do a layout for 20 items i can only pull info for that 20 items. If I am not managing the site and the guy wants to add 10 more items onto the database I then would have to add spots not on the database but on the html page itself. if i added the extra spots on the html and there's no info on the database it would be a bunch of blank spots. unless there's some css or something to hide the div if the data is empty or something.
as you can see there are 20 cars the php pulls all the data from the database to populates all the fields. but if you take away 5 cars there would be 5 empty fields

[mlseim]

It works like this ....

You put rows of items into a database (like MySQLi). That database can have 100, 1000, or a million items ... it doesn't matter.

A PHP script queries that database. Which means it pulls out rows based on a particular search, a range of prices, by color, by mileage, whatever. The query returns the rows to PHP as an array. The array only contains the items that you want to display (based on a search or some 'selection' of items). The PHP script knows how many there are in the array.

The PHP script loops through that array and dynamically generates the HTML it needs to display the items however you want.

A good analogy is this website you're using right now (web design forums). The page you are now looking at is created by a PHP script. The post you are viewing right now is taken from a MySQL database and displayed on this web page. Everyone using web design forums right now is executing the same PHP script. It just serves each of us different content depending on what we need to see. If you look up at the URL in your browser address bar, you'll see various codes, numbers, titles that PHP uses to pick out information from the database.