how to insert and update record through trigger in a custom object in salesforce

Question

Hi I have tried the below code

trigger CreateRecord on Account (before insert,before update) {
 List<Account> CreateAcc = new List<Account>();
    For(Account acc:trigger.new)
      {
       acc.Name='abc';
       CreateAcc.add(acc);
      }
    insert CreateAcc;  
 }

but the above code is creating the following error: Review all error messages below to correct your data. Apex trigger CreateRecord caused an unexpected exception, contact your administrator: CreateRecord: execution of BeforeInsert caused by: System.SObjectException: DML statement cannot operate on trigger.new or trigger.old: Trigger.CreateRecord: line 9, column 1 enter code here

Please help me through the code as where I am wrong.

Answer 1

Why don't you try to call a methods or function from a controller rather than putting your stuffs in trigger?

On my end, I would do it like this..

Create a utility controller with a methods that will insert a record

public class UtilityController
{
    @future (callout = true)
    public static void CreateRecord()
    {
       //Put your stuffs here...
    }
}

And then in the trigger, just call that method

trigger Account_CreateNewRecord on Account (before insert,before update) {
    Utility.CreateRecord();
}

Note that you can only call a method/function from another class if it has a future anotation.

I often use triggers like this to call a method on or before/after statement. That way you're trigger was just focus on executing a method/function when it was triggered. See Apex Developers Guide for more information about apex triggers.

Answer 2

Remove the update DML statement at the end. By using the "before" trigger to modify the Trigger.new objects, you don't need to explicitly perform an update, insert a DML statement. When the trigger ends, it will implicitly update or insert the data as you have modified the values.

trigger CreateRecord on Account (before insert,before update) {
 List<Account> CreateAcc = new List<Account>();
    For(Account acc:trigger.new)
      {
       acc.Name='abc';
       CreateAcc.add(acc);
      }
    //insert CreateAcc;  removed this line.
 }