Why we cant insert/update fields in after triggers in that Salesforce Sobject?

Hello Shariq,

You may be wondering why so many triggers are before triggers. There’s a good reason – they’re simpler to use. If you need to make any changes to a record entering your after trigger, you have to do a DML statement. This isn’t necessary in a before trigger – changes to records entering your trigger always save!

The specific use case of an after trigger is when you need to associate any record to a record being created in your trigger. Here’s an example:

// Automatically create an Opp when an Account is created
trigger AutoOpp on Account(after insert) {
    List<Opportunity> newOpps = new List<Opportunity>();
    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;
}