If you are coming up with solutions like the PHP posted above, then I don't think we are ones to be telling you what you should be using. I personally would travel the PHP route, although the solution you have provided is more complex than I would like a file based solution to be. Personally, if you desire the functionality of the solution you have provided, a MySQL (as oppose to file) backend would be much more appropriate.
The primary purpose of the DATA statement is to give names to constants; instead of referring to pi as 3.141592653589793 at every appearance, the variable PI can be given that value with a DATA statement and used instead of the longer form of the constant. This also simplifies modifying the program, should the value of pi change.
-- FORTRAN manual for Xerox Computers