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Noppadol Weerakitti
Having
a web site is not a big deal. You
can hire students from a university to do the work. To be honest, some
students can do very good work for less expense. However, what happens
after you have a web site is really a big deal.
To make you have a clear picture of the difference between a normal static
web site and a dynamic web application, I will use a Telephone Book application
as an example.
A static web page Telephone book is just simply created with pure HTML
which combines data and “decoration” in the same file.
Click Here to jump to a
sample static Telephone Book web page and
Here to a dynamic one. You can see that both of them look the same to
the user view. However, there’s a big difference from the administration
view.
For example, adding new staff to the sample static Telephone Book is not
a simple task. Why? Because the page lists the staff information in two
different colors which makes the code of the page look look this:
The above code tells the browser to display the data row by row in different
colors like this:
| Angsana Narksang |
| Buncha Sangdee |
Because the
rows have to be sorted by name, then a new staff name Aumaporn Buawlert
has to be inserted between Angsana and Buncha.
The new page should be like this.
| Angsana Narksang |
| Aumaporn Buawlert |
| Buncha Sangdee |
All
right, that means you have to change the color of all rows after Buncha
and do it again and again when a new staff is added to the page. Not
a good way, isn’t it ?
How about the dynamic page ? Oh, it’s a lot easier. Let’s take a look
at the code that generates the page:
Response.Write “
Else
Response.Write “
End If % >
RS.MoveNext
Loop % >
Hey, don’t worry about the code. It’s just syntax. Look at the idea
behind it first, OK. The
combination of HTML (black color) and Active Server Pages script (blue
color) shown above is the main part which will produce the same result
as the static page. OK, let’s see what it really does.
First of all, all required rows of data will be generated as a Recordset,
in this example called RS which is the result of the query “SELECT
* FROM Tel_Book”. In another words RS is a collection of all records
in Tel_Book table. (Although, the code for generating the Recordset
is not shown here, it’s just 2 or 3 lines of coding)
After
having a Recordset, it is used in the “For” loop to produce
rows of records that are placed inside the HTML table.
For the “decoration”, the script checks the value of a variable
named index and changes the row’s background color to either “#FFFFCC”
or “#FFCCCC”. This can make sure that any change in data will not
cause any effect in the colors or vice versa, like the static page.
And as you may know, this brings our application close to the basic
principle of Object Oriented Programing or OOP, in some sense. And
more than that, to add the new record is much easier than painfully
editing the HTML file manually like you have to do with the static
web page.
You can do it on our
Example Page by just simply clicking the “>Add
new staff” button located at the end of the table and fill
in the form. After that the new staff name will be inserted into the
page automatically, in the right position, right color and … right
time.
Try it now!
With the
same idea, you can add more functions to the page, for instance, editing
the existing record, deleting the record which is ju1st a piece of
cake.
And that’s it. Dynamic Web Application.
