The  core  of  the  system  is  written  in  PHP  and  is  centred  around  two  main  scripts: 

queries.php,  which  runs and returns queries on the main database and multishop.php, 

which executes search queries across single or multiple XML databases. The following is 

a description of how these scripts work, from top to bottom. 

4.2.2 queries.php  

The queries script handles forms submitted by users, translates them into MySQL queries 

which it then runs on the MySQL database, before returning the results in HTML to the 

Apache server, which sends them out to the user`s browser window. Many of the larger 

chunks of code are split into separate files which are then included and evaluated inline 

by  PHP,  with  a  command  of the form: include( filename.inc ). The first step taken by 

the script is to check whether it has been requested with or without a HTTP query string   

the web equivalent of parameters to a function, not to be confused with an SQL query. If 

there  is  no  query  string,  just  the  search  form  and  a  welcome  message  will  be  returned, 

formatted  in  HTML,  prompting  the  user  to  enter  some  search  criteria  in  the  form 

contained in form.inc. form.inc has a little PHP code to refill the elements of the form 

with the contents of whatever query has just been made. Once a query has been made, the 

HTML form sends its contents back around into the queries.php page in the form of a 

HTTP query string.  

A typical HTTP request would look like this: 

http://localhost/queries.php?what=computer&searchby=location&where=malahide&your

area=01&radius=thisarea&sortby=default

This is how the request breaks down: 

   http://     the  Hypertext  Transfer  Protocol,  as  distinct  from  ftp://  (File  Transfer 

Protocol), telnet:// (remote Unix login) , imap:// (Internet Mail Access Protocol) etc. 

   localhost/     the  server  name;  could  equally  be 

www.advancedgoldenpages.com

  or 

134.226.83.50. 

   queries.php   the requested file, in this case a script that the Apache webserver will 

recognise and execute through its PHP module. 

   ?   denotes the start of the HTTP query string, which contains the following variables 

and their values, separated by ampersands 

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