Hi All

Over the last few months I have been teaching myself Apex.  I have some PHP/javascript experience but apart from that this is all pretty new.

I had some live use cases that required the creation of a trigger that I managed to write succesfully and deploy to production.  Everything works ok, but have no idea whether my code is best practice.  I have attempted to write them to allow bulk request and written the appropriate test classes, but beyond that I don't know if they are written well.

If any one has any comments/suggestions it would be great to get some feedback.  Also there might be people out there who can benefit from the code.

Use Case.

When an Account is updated in Salesforce, all child opportunities should be updated with a specific value. This value is created from an external id on the account and a text value on the opportunity.

trigger updateOpportunityids on Account (after update) {
//soql statement creates a list of all opportunities for the trigger Accounts
List<Opportunity> holdopps = [select id, service_id__c, service__c, account.company_id__c from opportunity where Account.ID IN :Trigger.newMap.keySet()];
// loop through holdopps, assigning each record to the o variable
for (Opportunity o :holdopps) {
// if the service id of the o sobject variable = the combination of the service and company id	
	if (o.Service_id__c != o.Service__c+o.account.company_id__c && o.account.company_id__c != NULL){
// add the serviceid variable to the current o sObject 
o.Service_id__c = (o.Service__c+o.account.company_id__c);
	}	
}
//Update Opportunities using the holdopps array
try {update holdopps; }
//Exception Handling
catch (DmlException e){
}
}

And the test class

public with sharing class updateOpportunityidstest {
static testMethod void testserviceid() {
    //create holdopps list
    List<Opportunity> holdopps = new List<Opportunity>();
    
    //Create new Accounts
    Account a = new Account(Name='A Name', company_id__c = 9999);
    Account b = new Account(Name='B Name', company_id__c = 10000);
insert a;
insert b;
    
    //Create Opportunity
    Opportunity o = new Opportunity (Name='O Name', Service__c='ii', Service_id__c='', AccountId=a.id);
    o.StageName = 'Prospecting';
    o.CloseDate = Date.newInstance(2010,06,06);
    o.ExpectedUsage__c = 5;
    o.Nett_Seat_Fee__c = 5;
    insert o;
    
        //Create Error Opportunity
    Opportunity p = new Opportunity (Name='P Name', Service__c='ii', Service_id__c='', AccountId=a.id);
    p.StageName = '';
    p.CloseDate = Date.newInstance(2009,01,01);
    p.ExpectedUsage__c = 5;
    p.Nett_Seat_Fee__c = 5;
    
//Update Account
Account c = new Account(Name='B Name', company_id__c = 10001, id = a.id);
update c;
Opportunity q = [select name, Service_id__c from Opportunity where id = :o.id];
system.assertEquals(q.Service_id__c, 'ii10001');
}
}

That's it, look foward to your feedback!

Cheers

Chris