Lesson: 47 | Update Phone Number of the Contacts when an Account is updated

Expected Outcome

Code

Apex Trigger

Trigger UpdatePhoneNumber on Account (before update) {

    UpdatePhoneNumberHandler.updatePhoneNumber(Trigger.new,Trigger.oldMap);
}

Apex Handler Class

public class UpdatePhoneNumberHandler {
    public void updatePhoneNumber(List<Account> newAccounts, Map<Id, Account> oldAccountsMap){
        List<Contact> contactsWithoutPhone = [SELECT Id, Phone FROM Contact WHERE AccountId IN :newAccounts AND Phone = null];
        for(Account acc : newAccounts){
            if(acc.Phone != oldAccountsMap.get(acc.Id).Phone) {
                for(Contact con : contactsWithoutPhone){
                      if(con.AccountId == acc.Id) {
                        con.Phone = acc.Phone;
                    }
                }
            }
        }
        update contactsWithoutPhone;
    }
}

Video