Easy steps to build Web Application using ASP
I become nervous when people talk about servers, server-side scripts or active technologies. It so happens sometimes that the term gives the shock and not the stuff inside. Surprising to me, Active Server Pages (ASP) does not scare me in anyway rather it helped me in building an interactive and dynamic weblication (i mean a web based application). People dont need a high end programming expertise to start their ASP programming. It needs a modest programming skills, the argument which you will agree at the end of this discussion incase if you dont agree now. This article helps you to start building ASP based web application. This article explain each steps with the sample code. A sample application is also listed along with this article. The source code and the database files are available for you to download and use it.
Let us get on with the businesss and start building our ASP application.
I assume you know HTML(Not a big deal to learn). In anycase you can cut and paste the samples given here and change the titles and labels wherever required.
To build a form to get information like name, e-mail, comments/feedback etc. from the vistor to your site. And store all the information in a database for our reference. This is something which most of us prefer to have in our site so that the site could be updated based on the user's feedback and suggestions.
Build a database with a table to store the details. Create Fields like Name, E-Mail, Comments, Product Choice etc in the table. Create another table with ProductCode and Product title as the fields. We are going to use this product table to populate the select box in the HTML form dynamically.
I am using Ms-Access to build my database.My database file is swynk1.mdb. And the tables i have created are Userinfo and Prodinfo.
Our next step is to create a directory in the "wwwroot" directory of IIS server. We need to give read and execute permission to this directory. Then all our files (.htm,.asp,.mdb,.gif etc) are to be copied to this directory.
Once the files are copied we need to create a Data Source Name.
Open the Control panel.Select the ODBC 32 icon from Control Panel and click System DSN Tab. We need to select the Sysem DSN because it is available to anyone using that Server. Data sources that you use with Web server hence need to be system data source. Select add and choose Microsoft Access Drvier from the list since we are using a Access database. Then we need to give a DSN name and has to select the Database file. I have given "swynk1" as the DSN name. This name you will use in the ASP file to get connected to the database.
After the DSN is created now it is time to start coding.
First let us create a HTML Form to get the information from the user.
Going by our objective we need to create two text boxes to collect name and email information, one select box to get user's product choice and one another textarea box to get user's comments/feedback. Apart from these we need to create two buttons to submit and clear the contents.
The below listing gives the HTML for the Form:
<%@ Language=VBScript %> &<lt;HTML> <HEAD> <TITLE> USER INFORMATION FORM </TITLE> </HEAD> <BODY> <H1><font color="red"> WELCOME TO TEST INC.</font> </H1> <FONT FACE="VERDANA,ARIAL" COLOR="BLUE">Thanks for taking time to fill in the feedback form</FONT> <br><br> <%set dbconn= Server.CreateObject("ADODB.Connection") dbconn.Open("swynk1") sqlstr="select ProductCode from Prodinfo" set rs=dbconn.Execute(sqlstr)%> <form action="submit.asp" method="post" name="fomr1"> <table> <tr> <td> Name:<br><br></td><td><INPUT type="text" name=text1><br><br></td></tr> <tr> <td>E-Mail Address :<br><br></td><td><INPUT type="text" name=text2><br><br><br></td></tr> <tr> <td>Which Product you liked the most?<br><br></td><td><SELECT name=select1> <%rs.MoveFirst do while not rs.EOF%> <OPTION value='<%=rs("ProductCode")%>'><%=rs("ProductCode")%></OPTION> <%rs.MoveNext Loop%> </SELECT><br><br></td></tr> <tr> <td>Comments/Suggestions:<br><br></td> <td><TEXTAREA rows=3 cols=30 name=textarea1> </TEXTAREA><br><br></td></tr> <tr> <td colspan=2 align=center><INPUT type="submit" value="Submit" name=submit1> <INPUT type="reset" value="Reset" name=reset1><br><br></td></tr> </table> </form> </BODY> </HTML>
This is how it looks in a browser.
Fig:User Form in Browser
I could hear you aksing why this file has a .asp extension. If you have a second look at the code you can very well notice scripts enclosed "<%" and "%>" delimiters. As I told you earlier we are dynamically populating the select box from the database. This is accomplished using ASP components. So we need to save this file with a .asp extension.
Let us go in depth and understand the ASP part of the above script.
The very first line in the listing is <%@ Language=VBScript %>. This statement will inform the server that "VBScript" is used as a default scripting language.
Then comes our actual code to talk to the database and fetch the data.
Here we will be using Database Access Component. Server.CreateObject will create an instance of the server component. In this case it will instantiate the Data Access Component. <%set dbconn= Server.CreateObject("ADODB.Connection")%>. This object will let us get connected to the database. Once the object is instantiated now we need to open the database that we will use in our application. It is what is done in the next statement <%dbconn.Open("swynk1")%>. Here we are using Open method and supplying the DSN name as the argument.
Once we are connected to the database we can execute query and fetch the required results. In our example we need to select all the Product Code from the Prodinfo Table. So the SQL statement will be sqlstr="select ProductCode from Prodinfo". The statement is stored in a variable "sqlstr" as a string.
Then, we use the Execute method of the Data Access Component and pass the variable to it. Alternatively you can also directly pass the Select statement to the Execute method. We are storing the erturn results in a recordset rs. All these are done in our next line of code.
Now we have the results in hand. And we need to assign them to the select box.
We create a do while loop which checks for the recordset's End of file. We assing the values to the Option tag using the syntax <%=rs("ProductCode">. This is actually <%=recordset("Fieldname")%>. Take note of the equal sign before the recordset. If you dont specify the equal sign the value will not get assigned. Then we move through the recordset one by one using rs.Movenext method.
This succesfully completes our job of dynamically populating the select box.
But now once the data are entered and the submit button is clicked, the information are transferred to the Server and in turn has to be copied to the table Userinfo.
So we specify "submit.asp" as our server file in the
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