Lesson: 18 | Account Name can not be changed

Apex Trigger

trigger AccountTrigger on Account (before update) {
    
    for(Account acOld : Trigger.old){
        for(Account acNew : Trigger.new){
            if(acOld.id == acNew.id && acOld.name != acNew.name){
                acNew.name.addError('Account name can not be updated');
            }
        } 
    }
    
}