WHAT IS AFTER UNDELETE EVENT IN APEX TRIGGER, EXPLAIN IT WITH AN EXAMPLE?

AFTER UNDELETE:

This event runs the block of code after the deleted data is undeleted. Operations such as validation can be performed under this event to prevent wrong entry inside the database.

SYNTAX:

trigger triggerName on objectName (after undelete) {

   // Block of code

}

SCENARIO:

We have the requirement that whenever a deleted account is restored we need to set  one of the existing Account as ” Parent account” on the restored account.

APEX TRIGGER:

trigger AccountMainTrigger on Account (after undelete) { // Specifying the event.

    createContactClass obj=new createContactClass(); // Creating the instance of the class.

    if(trigger.isafter && trigger.isundelete) // Using context variable.

    {

     obj.method1(); // Calling apex class method.

    }

}

APEX CLASS:

public class createContactClass {

    public void method1(){

        Account obj=[SELECT id from Account where name='Test record creation' Limit 1]; // As default account need to be set as parent account on undeleted account hence using the above account with name 'Test record creation’.

        List<Account> accObjList=new List<Account>();

        accObjList=[SELECT id,ParentId from Account where id in:trigger.newmap.keyset()];

        for(Account acc:accObjList){

            if(acc.ParentId==null){

               acc.ParentId=obj.id;  // Setting the parent account on undeleted account.

            }

        }

        if(accObjList.size() > 0){ // Checking if the list has records.

            update accObjList; // Updating records.

        }

      

    }

}

Let us try to delete the below account,

   

Now to restore the deleted Account click on “Undo” as shown in the above image, it will get restored with parent Account what we have set using apex class. Please refer below images.