A Complete Database Accessing Web Site!

				
Background
     I set up the admissions site at
my college as what I like to think of as a web application as opposed to a bunch
of web pages. It is an ASP application that pulls all of its information- menu
titles and links, sub menu titles and links, and page content- from a database.
The information retrieved from the database is determined by parameters passed
through the query string. All of the menu links on the page link back to this
main page with a query string. For example, when you click on a main menu link
on the nav. bar, the page reloads with the main menu item's corresponding
content and all of the sub menu links listed under the main menu link. If you
are interested in how the tables are set up or the links are generated, please email
me.
There are administration pages that allow non-computer
savvy people to add and remove menu items and content to and from the database,
thus modifying the web site. These people were not satisfied with the menu items
simply being displayed in alphabetical order. They wanted to come up with their
own order.
How it works
I started out by adding an additional numerical field to
the menu tables in the database called zorder. A text box
corresponding to this field was added to the admin pages and the main page was
modified so that when it loaded the menu links, it sorted them by their zorder
field first and then their title field, whereas before they were sorted only by
the title field. If the user left the zorder field blank, I could
have done one of two things: give that item the next available zorder
number making it the last in the list; or give all items with blank zorder
values the same maximum zorder value thus making them all be
displayed alphabetically at the end.
I would have liked to just leave it at this, but I
foresaw two problems: these same non-computer savvy people having problems with
the idea of using a zorder field on the admin pages, and I would
get tired of manually updating all of the zorder values every time
I wanted to insert a menu link.
First of all, I labeled the zorder field on
the entry and edit forms Menu Position and I used a drop down box
of numbers to prevent users from entering erroneous values. The drop down box
contained the numbers from 1 to the maximum zorder number and
defaulted to the last possible number (1 plus the maximum zorder
numer) when they were adding a new item and to the existing zorder
number when they were modifying an item.
If the user enters a zorder number that is
already in use, you will have to update the following zorder
numbers accordingly. Given that selectedzorder refers to the zorder
number (menu position) that the user selected for the current record then the
following SQL query will perform the required update on the following menu
records:
 

 

 

 
Update
 main_menu set zorder=zorder+1where zorder >= selectedzorder;
 
 

To retrieve the maximum zorder value for
use in your drop down box you could use this query:
 

 

 

 
Select
 Max(zorder) from main_menu;
 
 

The same rules apply to the sub menu table with obvious
modifications.


Installation
To install the web application, just un-zip or un-Rar
the attatched file into a directory on your ASP-enabled server. I just have mine
in the root of my PWS.
If you set it up like I did you would access the demo
home page like this: http://localhost/default.asp

and the admin page like this: http://localhost/admin/default.asp
The database is stored in the admin directory. Password
protect the admin directory to protect the admin pages and the database. From
there it's all pretty self explanatory.
New features allow you to make that menu hierarchy as
deep as you like, and the order of menus is now changed with little arrow
buttons. I also re-wrote the interface on the front of the admin page and added
a site statistics page. Plus, you can cut and paste entire menu trees! This
makes it so easy to reorganize your site.
I'll apologize in advance for the lack of commenting and
some of the obscure code in places. I usually don't go to a lot of trouble on
comments on something this small and straight-forward not to mention it's the
product of quite a few late nights. If you find any blatently bad coding, please
let me know.
I worked pretty hard on this; if you decide to use part
of this code or the entire application please give credit where credit is due. I
am a very poor college student who likes computer toys and fine beers (a lot),
so if you decide to use this for commercial purposes (i.e. your business's
intranet or Internet site) you have to pay me something out of common courtesy
and your profits (heh, heh, j/k).
In any case, I'd love to see how you guys apply this. E-mail
me with links and descriptions! If you think this calls for another article, let
me know and I'll throw something together and submit it.
Thanks for all of you interest in my first article!!
Note: you must have ADO 2.0 or greater installed,
since the OLE-DB driver is used in connect.inc. You can download
ADO 2.0 for free, or you can just alter connect.inc so it uses a
DSNless connection or a System DSN.