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

AFTER INSERT:

This event runs the block of code after inserting data into the database. Operations such as creating or updating related records can be performed under this event.

SYNTAX:

trigger triggerName on objectName (after insert) {

   // Block of code

}

SCENARIO:

We are having the requirement to insert dummy Contact record as a related object on Account when the Account record is created.

APEX TRIGGER:

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

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

    if(trigger.isafter && trigger.isinsert) // Using context variables.

    {

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

    }

}

APEX CLASS:

 public class createContactClass {

    List<contact> conList=new List<contact>();

    public void method1(List<Account> accountList){ // Obtaining the list of Account records from trigger.new.

        for(Account obj:accountList){ // Iterating over account list.

            contact con=new contact(); // Creating a contact instance.

            con.FirstName='Testing contact';  // Creating contact record for each account

            con.LastName='Last Name';

            con.AccountId=obj.id; // Mapping contact torespective Account.

            conList.add(con); // Adding all contact in List. We should always perform DML operations on the collection of records to avoid hitting governor limit.

        }

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

            insert conList; // Inserting contact list.This is how we should perform DML operations on the collection of records.

        }

    }

}