ColdFusion Article

With ASP, you would use the following code to create a recordset object:

<%
set rsGetOrders = Server.CreateObject("ADODB.Recordset")
rsGetOrders.ActiveConnection = "northwind"
rsGetOrders.Source = "SELECT CustomerID, OrderDate from Orders" 
rsGetOrders.CursorLocation = 2
rsGetOrders.LockType = 3
rsGetOrders.Open()
rsGetOrders_numRows = 0
%>

You use the recordset on a page by manually looping through your resultset (note that the following is VBScript):

<table>
<%
While (NOT rsGetOrders.EOF))
%>
        <tr>
          <td><%=(rsGetOrders.Fields.Item("CustomerID").Value)%></td>
          <td><%=(rsGetOrders.Fields.Item("OrderDate").Value)%></td>
        </tr>
<%
rsGetOrders.MoveNext()
Wend
%>
</table>
              

Finally, when you're done with the resultset, you destroy the object and clear the memory space on the server (in this example, you're setting rsGetOrders = Nothing) as follows:

<%
rsGetOrders.Close()
Set rsGetOrders = Nothing
%>

Now, we'll do the same thing with ColdFusion code.  Remember that ColdFusion tags are the equivalent of a server-side object in ASP. To perform the same process in ColdFusion, use the cfquery tag instead of the recordset object you would have used in ASP:

<cfquery name= "rsGetOrders" datasource= "northwind">
SELECT CustomerID, OrderDate FROM Orders
</cfquery>

This code creates the recordset. Displaying it is simple with ColdFusion, since looping is built into the ColdFusion tags.  It’s unnecessary to manually start or stop the loop as you did in ASP. You simply print the results with a cfoutput tag, as follows:

<table>
			  
<!---The cfoutput query prints the query results.  Notice that the query
attribute specifies the query that it is outputting--->

<cfoutput query="rsGetOrders">
        <tr>
          <td>#rsGetOrders.CustomerID#</td>
          <td>#rsGetOrders.OrderDate#</td>
        </tr>
</cfoutput>
</table>

The ColdFusion code has several advantages that are evident right from the start:

• It's shorter and more concise.
• It's easier to understand exactly what the code does, even without programming knowledge.
• You don't need to write cleanup code, and you don’t have to destroy your objects, because the ColdFusion server handles those details. 
• Although it's not apparent from the code, you can use the recordset again and again on the same page without resetting your pointers.  ASP would required you to use rsGetOrder.MoveFirst() to reset the pointer to perform the same operation.

<cfmail to="#form.tofield#"
 from="admin@mywebsite.com" 
 subject="Your order has been placed">
<cfinclude template="message.cfm">
</cfmail>

Note that you would need to specify a mail server in the ColdFusion administrator.  This is as simple as entering the mail server IP or internet address in the appropriate setting in the ColdFusion administrator. 

If you've ever sent e-mail from ASP, you know what's required. First, you'd have to know which e-mail component is registered on the server. This could be CDO, JMail, ASPMail, or any number of other mail components. You may even have a host that doesn’t have a mail component installed. In any case, each component has a different syntax for instantiating the object and a different syntax for using e-mail.  Needless to say, coding ASP for sending e-mail is involved.

Also note that in the ColdFusion example, that the body of the message is included as a separate file. This could just as easily have been hard-coded into the program, but with ColdFusion, you can include files with the cfinclude tag.  This can be a great, added bonus. For one thing, you can create conditional logic for the including the files.  In other words, you can access different includes files based on criteria that you establish, such as a value in a field from the database. You cannot do this in ASP, however.  For example, inside the ColdFusion message.cfm page, you might have code that appears as follows:

<cfswitch expression = #rsGetAllEmails.emailtext#>
     <cfcase value="A05">
          <cfinclude template="orders_5day.cfm">
     </cfcase> 
     <cfcase value="A15">
          <cfinclude template="orders_15day.cfm">
     </cfcase>
     <cfcase value="A30">
          <cfinclude template="orders_30day.cfm">
     </cfcase>
     <cfcase value="A45">
          <cfinclude template="orders_45day.cfm">
     </cfcase>
</cfswitch>

Using conditional includes can be extremely useful in maintaining your application. Using include files in ColdFusion causes no performance degradation, so you can package your logic within them.  Later, you'll see how you can make your code even more flexible in the discussion on ColdFusion Components, a new feature in ColdFusion MX.

One thing that will become apparent after you've created a couple of ColdFusion sites -- most of the functionality that requires the use of objects, or third party components in ASP, is built into the ColdFusion language using the tag-based syntax. A few of the more powerful ColdFusion tags (some of them are new to ColdFusion MX) are listed below:

One of the biggest new developments in ColdFusion MX is that you can use JSP tag libraries with your ColdFusion pages. This means that a ColdFusion programmer can take advantage of any existing tag libraries, as well as create new ones. This is on top of all the ColdFusion tags and COM objects that are already in a ColdFusion programmer’s arsenal.

Another new, big feature in ColdFusion MX is ColdFusion Components (CFCs).  CFCs are self-documenting and  self-contained.  You can use CFCs through any ColdFusion pages on the ColdFusion server.  Other technologies can access your ColdFusion components if you publish them as web services (for instance, a Macromedia Flash application may use a ColdFusion component to run a database query based on a user's request).

Create CFCs with the cfcomponent tag, and save them with a CFC extension.  Include your CFML logic (such as a cfquery tag, conditional code, and so forth) within a cffunction tag inside of the cfcomponent tag inside the CFC file.  Then, any ColdFusion page on your server can call the functions (also called methods) within the CFC.  For full details on how to use CFCs, refer to the other articles in the ColdFusion Developer Center, and to the ColdFusion MX documentation book, Developing ColdFusion MX applications. 

Developing ColdFusion components that produce web services has one major advantage over producing web services in other technologies – you can create a ColdFusion component web service with standard CFML code in a fraction of the time.  Simply add the attribute access=remote to the cffunction tag to activate the CFC as a web service.  The following is a simple CFC that reads the contents of a directory and returns a list of JPG files in that directory:

><cfcomponent>
  <cffunction name="getJPGList" returnType="string">
    <cfdirectory name="fileList"
       action="list"
       directory="H:\public_jpegs" 
       filter="*.jpg"> 
   <cfreturn #ValueList(fileList.name)#>
  </cffunction>
</cfcomponent>

Save this file as getFiles.cfc (Note: You'll need to change the directory based on your directory structure). You can use this CFC on your ColdFusion page to get a comma-separated list of all JPEG files in the H:\public_jpegs directory. To invoke the CFC on a ColdFusion page, use this simple code:

<cfinvoke component="getFiles" method="getJPGList"
 ReturnVariable ="theList"/>

After the cfinvoke tag, use the variable, theList, which contains the entire directory of JPEGs. Transform this simple component into a web service.  Doing so makes the information accessible to anyone on the Internet using any capable technology.  Simply add access="remote" to the cffunction tag in the CFC. ColdFusion MX takes care of all the details, including creating the WDSL file for you. You've successfully published a web service that lists the contents of one of your directories. This was a simple example.  Yet, compared to that of another language, it illustrates the simplicity and power inherent in ColdFusion code. Read more about using ColdFusion components in the ColdFusion Developer Center.

About the author
Tom Muck is co-author of three UltraDev books including the bestseller, Dreamweaver UltraDev4: The Complete Reference.  He is an extensibility expert focused on the integration of Macromedia products with ColdFusion and other languages, applications, and technologies.  Tom has been recognized for this expertise as the 2000 recipient of Macromedia's Best UltraDev Extension Award.  He also authors articles and speaks at conferences on this and related subjects.  As Senior Applications Developer for Integram in Northern Virginia, Tom develops back-end applications for expedited, electronic communications. Tom also runs the Basic-UltraDev site with co-author Ray West and is an advisor for MX inSite magazine.