Deleteing multiple SObjects in batch apex

Question

I have the following code that executes exactly how I need it to, the only issue is I receive "Apex CPU time limit exceeded" when I run the delete on Accounts, EmailMessage and update Cases. After looking into the error it looks like I need to move this code into a batch job however all of the documentation around batch jobs only ever delete one SObject. How can I execute this code in a batch job since I am looking at 3 SObjects?

The code basically deletes any accounts, cases and emailmessages that are over 30 days old. If the account has a new case then we ignore the old cases until that new case is 30 days old.

    Date threshold = Date.today().addDays(-30);
    List<Account> accountsToDelete = new List<Account>();
    List<Case> casesToDelete = new List<Case>();
    List<EmailMessage> messagesToDelete = new List<EmailMessage>();
    Integer count = 0;
    Integer count2 = 0;
    Integer count3 = 0;
    for (Account account : [
        SELECT (SELECT LastModifiedDate FROM Cases ORDER BY LastModifiedDate DESC)
        FROM Account WHERE Id IN (
            SELECT AccountId FROM Case
            WHERE LastModifiedDate < :threshold
            AND Account.Name Like '%Test%'

        )
    ]){
        if (account.Cases[0].LastModifiedDate < threshold)
        {
            accountsToDelete.add(account);
            casesToDelete.addAll(account.Cases);
        }
    }
    messagesToDelete = [ SELECT Id, ParentId FROM EmailMessage WHERE ParentId IN : casesToDelete];

    for(Case c: casesToDelete){
        c.OwnerId = '005i0000001I5Y3';
        c.Guest_Email__c = '';
        c.Guest_Name__c = 'Purged';
    }

    for(Account a: accountsToDelete){
        a.Id = '0018A000006Xvgo';
    }

    for(EmailMessage e: messagesToDelete){
        e.FromAddress = '';
        e.ToAddress = ''
    }


    update casesToDelete;
    delete accountsToDelete;
    delete messagesToDelete;

Answer 1

When dealing with parent and child records in most batch processes, you just need to first query for the parent, and then its children:

global class DeleteOldRecords implements Database.Batchable<SObject> {
    global Database.QueryLocator start(Database.BatchableContext bc) {
        return Database.getQueryLocator(
            [SELECT Id FROM Account 
             WHERE LastModifiedDate < LAST_N_DAYS:30 AND 
             Name LIKE '%test%']);
    }
    global void execute(Database.BatchableContext bc, Account[] scope) {
        Set<Id> accountIdsToKeep = new Map<Id, AggregateResult>(
            [SELECT AccountId Id FROM Case WHERE AccountId IN :scope
             AND LastModifiedDate = LAST_N_DAYS:30 GROUP BY AccountId]).keySet();
        Set<Id> accountIdsToDelete = new Map<Id, Account>(scope).keySet();
        accountIdsToDelete.removeAll(accountIdsToKeep);
        if(!accountIdsToDelete.isEmpty()) {
            Case[] casesToDelete = [SELECT Id FROM Case WHERE AccountId IN :accountIdsToDelete];
            EmailMessage[] emailsToDelete = [SELECT Id FROM EmailMessage WHERE ParentId IN :casesToDelete];
            Account[] accountsToDelete = [SELECT Id FROM Account WHERE Id IN :accountIdsToDelete];
            delete emailsToDelete;
            delete casesToDelete;
            delete accountsToDelete;
        }
    }
    global void finish(Database.BatchableContext bc) {
    }
}

When you run this, you can adjust the batch size to figure out what the optimal number is, since batch processes still have governor limits.

Some general notes:

• Don't use hard-coded ID values, because they may change or break your tests.
• Don't change the Id field of a record before deleting it, as you'll delete an entirely different record.
• Delete doesn't save new field values, so if that's your intent, you must do so before the delete occurs.
• I'm pretty sure you don't need to delete the emails, since the cascade delete on cases should probably work. You might actually be doing more work than necessary.