Database.insert issue

Question

I have this piece of code,where i am trying to insert a record(which throws me duplicate issue).But i am trying to insert it using database.insert

EntitySubscription e = [select id from EntitySubscription where ParentId = 'a0CM0000005hyYAMAY' and SubscriberId= '005M0000005BqhVIAS'];
//e exists
EntitySubscription a = new EntitySubscription(ParentId = 'a0CM0000005hyYAMAY',SubscriberId= '005M0000005BqhVIAS');
List<EntitySubscription> collaborationBetMembers = new List<EntitySubscription>();
collaborationBetMembers.add(a);
Database.Saveresult[] saveResult; 
saveResult = Database.insert(collaborationBetMembers);
system.debug(saveresult);

Now my issue is above code throws an exception but when i specify false parameter explicityly in

saveResult = Database.insert(collaborationBetMembers,false);

It doesnt throw exception. which is confusing because this documentation shows,its false my default..so my assumption is you dont need to write it explicitly.any idea why http://www.salesforce.com/us/developer/docs/apexcode/index_Left.htm#CSHID=apex_methods_system_database_saveresult.htm|StartTopic=Content%2Fapex_methods_system_database_saveresult.htm|SkinName=webhelp

Exception i get is below

System.DmlException: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, duplicate value found: duplicates value on record with id: : []:

Answer 1

This code does throw exception. It is just handled and saved in SaveResult Object. Quite similarly like try{} Catch(exception ex){} - here it also does throw exception but don't break session because you handle it.

Solution for you is to create method that will check SaveResult and look for error.

for(Database.SaveResult sr : saveResult){            
    if (!sr.isSuccess()) {
        /** Some tasks if Error found **/
    }
}