When a Case is created on any Account, put the latest case number on the Account in the ‘Latest Case Number’ field triggers in Salesforce

 Here’s an Apex Trigger that automatically updates the Latest Case Number field on the Account when a Case is created for that Account.

trigger UpdateLatestCaseNumber on Case (after insert) {

    // Create a map to hold Account Ids and their latest case numbers

    Map<Id, String> accountToLatestCaseNumber = new Map<Id, String>();

    // Loop through all inserted cases

    for (Case c : Trigger.new) {

        // Check if the Case is linked to an Account

        if (c.AccountId != null) {

            accountToLatestCaseNumber.put(c.AccountId, c.CaseNumber);

        }

    }

    // After processing the cases, update the Account records with the latest case number

    if (!accountToLatestCaseNumber.isEmpty()) {

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

        // Loop through the map and create Account records to update

        for (Id accountId : accountToLatestCaseNumber.keySet()) {

            Account accToUpdate = new Account(Id = accountId);

            accToUpdate.Latest_Case_Number__c = accountToLatestCaseNumber.get(accountId);

            accountsToUpdate.add(accToUpdate);

        }

        // Perform bulk update on Accounts

        if (!accountsToUpdate.isEmpty()) {

            update accountsToUpdate;

        }

    }

}

Explanation of the Code

1. Trigger Event:

   • This trigger is set to run on the after insert event because the Case is inserted first, and then the Account is updated with the latest Case Number.

2. Logic:

   • The trigger iterates over each Case created in Trigger.new.
   • For each Case, it checks if there is an associated Account (AccountId).
   • The Case Number of each Case is stored in a map with the AccountId as the key.
   • After processing all Cases, the trigger updates the Account with the latest Case Number stored in the map.

3. Bulk Processing:

• The trigger handles bulk processing by using a map to store the AccountId and its latest Case Number. After all records are processed, a single bulk update is performed on the Account records.

@isTest

private class UpdateLatestCaseNumberTest {

    @isTest

    static void testUpdateLatestCaseNumber() {

        // Create Account

        Account testAccount = new Account(Name = 'Test Account');

        insert testAccount;

        // Create Cases for the Account

        Case case1 = new Case(AccountId = testAccount.Id, CaseNumber = 'C-001', Status = 'New');

        Case case2 = new Case(AccountId = testAccount.Id, CaseNumber = 'C-002', Status = 'New');

        insert new List<Case>{case1, case2};

        // Query the Account to check the Latest Case Number

        Account updatedAccount = [SELECT Latest_Case_Number__c FROM Account WHERE Id = :testAccount.Id];

        // Verify that the Latest Case Number is updated to the latest Case Number

        System.assertEquals('C-002', updatedAccount.Latest_Case_Number__c, 'The Latest Case Number should be C-002');

    }

}