Visualforce Tip: Custom Components + DML

I built a Visualforce custom component today and ran in to (what should have been) a fairly trivial problem.

As you can see below, my Visualforce custom component has a CommandLink and the controller has a corresponding action method that updates a field on the displayed Contact record.

CommandLink:
<apex:commandlink value="Associate External Id to Contact" action="{!associate}">

Action Method:
public PageReference associate()
{
c.ExternalId__c = ExternalId;
update c;

return ApexPages.currentPage();
}

There's not much complexity here, but every time I clicked on the ComandLink, I kept getting this error:

System.Exception: DML currently not allowed

I had read the documentation, scoured the message boards, thoroughly searched the wiki and was about to submit my own question to the message boards when I gave the documentation one last look. To my joy/chagrin, I discovered the allowDML attribute on the Visualforce component standard component. It has this description:

If this attribute is set to true, you can include DML within the component. The default is false.

Here's what my component tag looks like now:
<apex:component controller="MyContactController" allowDML="true">

Deploy Force.com Applications to Production Faster

I have a post over on the Force.com blog titled "Deploying Force.com Applications to Production Faster." It was inspired by Steve Andersen's post about how he used the Force.com IDE to reduce his deployment process from 8 hours to 2 hours.

The Force.com Migration Tool is another useful tool for deploying from one salesforce.com environment to another. Both tools leverage the powerful Metadata API.