When to use “before” vs “after” triggers

When I set an Opportunity to complete and that same opportunity meets certain conditions, I need to create a clone of that opportunity with a different opportunity record type. Before or After trigger? Or both?

Hi David Liu,

Thanks for giving the clear picture of When to use before vs after triggers.
My doubt has vanished now. Finally, I am able to write Apex Trigger.

Thanks for sharing this article.

Hi David,

I have written your trigger in the below form – I am trying to bulkify the code! would that be correct too in this instance?

// Create an opp when an Account is created
trigger CreateOppWhenAccountCreated on Account (after insert) {

List newOpportunities = new List();

for (Account account : trigger.new) {
Opportunity opp = new Opportunity(Name=account.Name + ‘ opportunity’,
StageName=’Prospect’, CloseDate=Date.today() + 90,
AccountId=account.Id);
newOpportunities.add(opp);
}

insert newOpportunities;

} // end trigger

Thank you, Sinan

Hi David,

Good session from you. Below is my understanding out of ur session.

1. Before trigger, if at all the triggered records had to follow some complex business rules / go with some modifications before it can be saved. Its a before save scenario.

2. After trigger, means a record is already saved to DB, what next? insert / update dependent objects, fire future calls (may be for some webservice calls / api for sync up with different systems etc) and so on.

Thanks,
Santhi C

Hi David
I came across these words Recursive Trigger and Circular Triggers ….. Can u explain me those things and where do we use them

trigger AutoOpp on Account(after insert) { List newOpps = new List();
for (Account acc : Trigger.new) {
Opportunity opp = new Opportunity();
opp.Name = acc.Name + ‘ Opportunity’;
opp.StageName = ‘Prospecting’;
opp.CloseDate = Date.today() + 90; opp.AccountId = acc.Id; // Use the trigger record’s ID newOpps.add(opp);
}
insert newOpps;
}

Error: Compile Error: Variable does not exist: Name at line 4 column 23

I m getting this why i m getting this error.?
please give me some examples to write the effective trigger

David,

I’m struggling with a trigger. I was thinking about whether doing an after insert would help but I think the issue is in the test class, rather than the trigger.

Here’s the scenario: when creating an event of type “New Member Briefing” I want the custom date field “Member Announcement Date” on the client’s contact record to be copied into the same field on the event record so I can do a report on the number of days between “new member announcement” and the date of the event (I have a UsableDueDate field and trigger set up to allow me to do this).

Below is my trigger so far. It’s based on somewhat a similar scenario I found online. I may have got confused because in the example I cribbed from the date field was going from child to parent not parent to child. It’s my first one, so please bear with me.

trigger NMBDateTrigger on Event (after insert) {

List EventIDs = new List();
List updateNmbEvents = new List();
for (Event nmbEvent : trigger.new) {
EventIDs.add(nmbEvent.Id);
}
Map ContactUpdateMap = new Map();
for (Contact newmember : [Select ID, member_announcement_date__c FROM Contact WHERE ID in:EventIDs])
{
ContactUpdateMap.put(newmember.ID, newmember);
}
for (Event nmbEvent : trigger.new) {
Contact updateNmbEvent = ContactUpdateMap.get(nmbEvent.Id);
if (nmbEvent != null) {
if (nmbEvent.Type == ‘New Member Briefing’) {
updateNmbEvent.Member_Announcement_Date__c = nmbEvent.Member_Announcement_date__c;
update updateNmbEvents;
}
}
}
}

END OF TRIGGER

Here’s the test class so far.

@isTest
public class TestNMBDateTrigger{
static testMethod void testNmbDate() {
//create records to test
Contact c = new Contact();
c.FirstName =’John’;
c.LastName = ‘Smith’;
c.Member_Announcement_Date__c = System.Today();
insert c;

//create NMB event
Event nmbEvent = new Event();
nmbEvent.Subject = ‘Test NMB Event’;
nmbEvent.Type = ‘New Member Briefing’;

// David, do I need the ID for the contact first?
// If the test contact and event are created at the same time, how do I get this? I wouldn’t expect this to work, as it is.
nmbEvent.WhoId = ‘c.Id’;

try{
insert nmbEvent;
} catch (Exception e) {
System.debug(‘An error happened, as predicted!’);
}
List nmbEvents = [SELECT Id FROM Event WHERE (Member_Announcement_Date__c = TODAY)];
System.assertEquals(1,nmbEvents.size());
}
}

END OF TEST CLASS

I tried to run the code but got an error saying, “System.StringException: Invalid id: c.Id”, which makes sense since the event can’t get the contact ID for the WhoID until after the contact record is created. In real life, this isn’t an issue since the contact is there already but I can’t figure out how to test this. I’m extrapolating from an example test class, so I don’t think it’s finished yet.

Thanks for any help you can provide!

Ian