An Apex trigger is proposed to count the number of related contact records for an account to populate a field, since a rollup summary field cannot be used due to the lookup relationship between account and contact. The trigger would need to execute on contact record insert, update, and delete to accurately update the account field, as a process builder would fail to handle deletions. The target object for the trigger would be the account, and the trigger events would be on contact record changes.

1. APEX TRIGGER - SCENARIO 2
Roll-up Summary For Lookup Relationship

2. PROBLEM STATEMENT
• The Relationship between Account & Contact is Lookup with
Cascade Delete. Which means we can not create Rollup Summary
Field on Account Which Count Related Contact Record.
• Developer needs to build a Solution which Count Contact Record
Related to a Particular Account and then store into a field.

3. POSSIBLE SOLUTIONS
Process + Flow Builder Apex Trigger
No Coding Knowledge Requires Coding Knowledge
AppExchange Applications
•Rollup Summary Helper
•Declarative Rollup Summary

4. PROBLEM WITH PROCESS + FLOW
• Process Builder will only executes if a record is Created/
Updated.
• Process Builder will fail if a user is deleting a Record from the
System.

5. SOLUTION - APEX TRIGGER

6. FOLLOW UP QUESTIONS
• What will be target object ?
• What will be trigger events ?