I have two object 
1. Account
2. BCC (related object to acount)
Account has external id field "BCC customer code" and BCC object has field "BCC code" and "status".
Requirement : When BCC code status is active then only that BCC code should show in "BCC customer code" on Account detail page.
how to write trigger for this.
 

  public boolean hasMessages {
        get {
             return ApexPages.hasMessages();
        }

hi guys,
help me out in using standard controllers in vf trailhead getting a error of
Challenge not yet complete... here's what's wrong: 
The page does not include a bound owner's email variable for the Contact record
cheers...