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 and is linked to account using lookup Account__c.

APEX TRIGGER:

trigger AccountMainTrigger on Account (after delete) { 

    if (Trigger.isAfter && Trigger.isDelete) {

        AccountMainTriggerHandler handler = new AccountMainTriggerHandler();

        handler.deleteChildRecords(Trigger.old); // Passing deleted Account records to the handler method

    }

}

APEX CLASS:

public class AccountMainTriggerHandler {

    public void deleteChildRecords(List<Account> accList) {

        // Collecting Account IDs from the deleted Account records

        Set<Id> accountIds = new Set<Id>();

        for (Account acc : accList) {

            accountIds.add(acc.Id); // Adding Account IDs to the set

        }

        // Querying all related child records (Child_object__c) based on Account IDs

        List<Child_object__c> childRecords = [SELECT Id FROM Child_object__c WHERE Account__c IN :accountIds];

        // If there are child records, delete them

        if (!childRecords.isEmpty()) {

            try {

                delete childRecords; // Bulk DML delete operation

            } catch (DmlException e) {

                // Handle DML exception if necessary (e.g., logging or error handling)

                System.debug('Error during child record deletion: ' + e.getMessage());

            }

        }

    }

}

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

    

    

Let us understand with another exaple,

Let's create an AFTER DELETE trigger for the Opportunity object in Salesforce. This trigger will log the details of deleted Opportunity records into a custom object called OpportunityAudit__c for auditing purposes.

Create the Custom Object

First, create a custom object OpportunityAudit__c with the following fields:

• Opportunity Name (Text)
• Opportunity Stage (Text)
• Opportunity ID (Text)
• Deleted At (Date/Time)

trigger OpportunityAfterDelete on Opportunity (after delete) {

 

    // List to store OpportunityAudit__c records

    List<OpportunityAudit__c> opportunityAudits = new List<OpportunityAudit__c>();

 

    // Loop through the deleted Opportunity records

    for (Opportunity opp : Trigger.old) {

        // Create a new OpportunityAudit__c record for each deleted Opportunity

        OpportunityAudit__c auditRecord = new OpportunityAudit__c(

            Opportunity_Name__c = opp.Name,

            Opportunity_Stage__c = opp.StageName,

            Opportunity_ID__c = opp.Id,

            Deleted_At__c = System.now() // Timestamp when the Opportunity was deleted

        );

 

        // Add the audit record to the list

        opportunityAudits.add(auditRecord);

    }

 

    // Insert the audit records into the OpportunityAudit__c object

    if (!opportunityAudits.isEmpty()) {

        insert opportunityAudits;

    }

}