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

AFTER DELETE:

This event runs the block of code after the data is deleted from the database. Operations such deleting related records can be handled using this event.

SYNTAX:

trigger triggerName on objectName (after delete) {

   // Block of code

}

SCENARIO:

We are having the requirement to delete the child object records associated with Account record when the Account record is deleted. “Childobject” is a related list on Account.

APEX TRIGGER:

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

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

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

    {

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

    }

}

APEX CLASS:

public class createContactClass {

    List<Child_object__c> cObjToDeleteList=new List<Child_object__c>();

    public void method1(List<Account> accList){ // Getting list of account records.

        for(Account acc:accList){ // Iterating over account list.

            for(Child_object__c cs:[Select id from Child_object__c where Account__c=:acc.id]){

                cObjToDeleteList.add(cs); // Adding related child object associated to an account in a list.

            }

        }

        if(cObjToDeleteList.size() > 0){ // Checking if the list contains records.

            delete cObjToDeleteList; // Deleting records.

        }

      

    }

}

Now let us try to delete an account record which has a child object associated with it as shown in the below image.