Hi All,

I have 2 custom objects by name 'Customer__c' and 'Address__c'.

Address object has a look up field of customer. It also has a picklist field 'Type__c' with values 'Primary' and 'Secondary' indicating the primary and secondary addresses for the customer object.

Now I want to restrict the customer to have only one 'Primary' address record but it can have multiple 'Secondary' address records. 

I have written the following trigger to accomplish this.

trigger primaryAddressDupPreventionV2 on Address__c (before insert, before update) {

	List<Address__c> Addr_List = new List<Address__c>();
	
	List<Address__c> addr_temp = System.Trigger.new;
    Customer__c cust = [select Id,Name from Customer__c where id=:addr_temp[0].Customer__c];

	try{
		for (Integer i=0;i<trigger.new.size();i++) {
			Addr_list = [Select Id, Name, Customer__c, Type__c from Address__c 
		                                where Customer__c =: cust.Id and Address__c.Type__c = 'Primary' and Id != null limit 1];
			system.debug('Addr List Size: '+Addr_list.size());
			system.debug('Addr List: '+Addr_list);
			
			if(Addr_List.size()== 0 && trigger.new[i].Type__c == 'Secondary'){
				trigger.new[i].Type__c.addError('Primary Address does not exist');
			}
			if(trigger.isInsert && Addr_List.size()>0 && Addr_List.get(0).Type__c == 'Primary' && trigger.new[i].Type__c == 'Primary'){
				trigger.new[i].Type__c.addError('Only one Primary Address should exist');
			}
		}
	}catch (DmlException e1) {
     	System.debug(e1.getMessage() );     
    }catch (TypeException e2) {
     	System.debug(e2.getMessage() );     
    }
}

 The trigger is working fine while inserting records. But fails during update operation.

Could anyone please let me know where I have gone wrong or any workaround to accomplish the same.

Any help will be highly appreciated.