Jump Start To ColdFusion MX: page 2

By: Clint Tredway
Published: 24th Sep 2000

Showing The Results Of A Query

Ok, now that we know how to query a database, let's see how we can show the results of that query. Remember the <cfoutput> tag we talked about earlier in this article? This tag will loop through a recordset when the query attribute is used. Here's how to set up the output of our query from earlier:

<cfoutput query="myQuery">
#col1# #col2#<br>
</cfoutput>

That's all you have to do to output a result set from a query -- It's that simple! Any HTML tag can be placed inside a <cfoutput> tag as well. For example:

<cfoutput query="myQuery">
<table width="100%" cellpadding="0" cellspacing="0" border="0">
<tr>
<td>#col1#</td>
<td>#col2#</td>
<tr>
</table>
</cfoutput>

The <cfoutput> tag is a very powerful tag that has many cool features that are beyond the scope of this article. I will compose a more advanced article with these features explained in depth another day.

On the Winodws platform variables are not case sensitive. So myquery and myQuery refer to the same variable. You can have the same variable in different scopes though. I would not recommend doing this, but it is possible. For instance, you can have form.myvar and url.myvar, but this is not good coding practice -- I just wanted to state that it was indeed possible.

Sending Email
Sending email is a very common task that many developers have to do in many of the applications we build. In ColdFusion, sending email is very simple. Just like the other tags that we have used previously in this article, this tag is called what it does; <cfmail>. The <cfmail> tag is what allows developers to send email through their applications. Here is how to use this tag:

<cfmail from="me@me.com" to="you@you.com" subject="This is an email from ColdFusion">
Hello From ColdFusion MX!
</cfmail>

This will send an email to the 'to' address with the body of 'Hello From ColdFusion MX'. There are other attributes that this tag can use are bcc, cc, type (text or HTML), query, timeout, startrow, endrow, and many others. This is a powerful tag but it was not design to be a mail-sending engine -- there are third-party mail tags that are much better than the default <cfmail> tag but at least you do not have to buy a third-party tool to send mail out of the box.

Looping In ColdFusion

The next topic that I am going to cover is looping in ColdFusion. To loop through just about anything in ColdFusion, you would use the <cfloop> tag. With this tag you can loop through a query, a list, an array, a structure, do for loops, and conditional loops. I am going to cover just the basics here. To loop through a query use the query attribute of <cfloop> like this:

<cfloop query="myQuery">
HTML and CF code here
</cfloop>

Its that simple. Now, let's go through how to loop from one number to another and output that number:

<cfloop from="1" to="100" index="number">
<cfoutput>#number#</cfoutput><br>
</cfloop>

This is similar to a for loop that you would use in PHP or ASP. The index attribute is used in other pieces of code like output, or an if statement. Here’s how to loop through a list:

<cfset myList="1,2,3,4,5,6,7,8,9">
<cfloop list="#myList#" index="listItem">
<cfoutput>#listItem#</cfoutput>
</cfloop>

There is an optional attribute – delimiter -- that allows you to specify the delimiter for a given list. The default delimiter is a comma. Now, to loop over a structure you would use the collection and item attributes like this:

<cfset products = StructNew()>
<cfset val = StructInsert(products, "Appliances ", "Dryer ")>
<cfset val = StructInsert(products, "Furniture ", "Couch")>
<cfset val = StructInsert(products, "Electronics ", "Tv ")>

<cfloop collection="#products#" item="cartitem">
#products#<br>
#StructFind(products, cartitem)#<br><br>
</cfloop>

I know that I have not covered everything about loops, but this gives you the basics to start using them. In a more advanced article I delve into loops in greater detail.

Form Handling

When a form is submitted, ColdFusion places all of the form variables in the 'form' scope. If I had a form field named 'username', I would access this value like this:

#form.username#

For the record, you do not have to use the scope to gain access to this variable, although using the scope is a good programming practice. ASP and PHP developers will be familiar with this content for the Request and $_POST collections respectively.

ColdFusion also places all form values submitted into a structure. This is very helpful when building dynamic forms. Lets go over a simple code example:

Place this in a page called myname.cfm:

<form action="test.cfm" method="post">
Enter Your Name:<input type="text" name="myname" size="30"><br>
<input type="submit" name="go" value="Submit Name">
</form>

Here is test.cfm:

<cfif IsDefined('form.myname')>
Hello <cfoutput>#form.myname#</cfoutput>
<cfelse>
Please enter your name.
</cfif>

When the form is submitted the if block will see that the variable 'form.myname' is present and it will output 'Hello Your Name Here'. Pretty simple isn't it?

Conditional Statements
Let’s now look at using conditional if statements. I just used if and an else in the previous coding example. Using if statements in ColdFusion is very easy. The tag syntax is as follows:

<cfif expression goes here>
code to execute if the if statement is true
</cfif>

The if statements can get much more complicated than the example I just showed you, but you get the idea. You can also have else's and elseif's in there as well. Here's a short example:

<cfif IsDefined('form.myname')>
Hello <cfoutput>#form.myname#</cfoutput>
<cfelseif Not IsDefined('form.myname')>
Please enter your name.
<cfelse>
Something else goes here.
</cfif> 

Conclusion

Well, that is it for the first part of this article. In part two I’m going to cover file handling, email, sessions, and some other topics. I hope this gets your interest peeked about ColdFusion!

Read more from Clint Tredway here