Drills › Automate with triggers

Stop recursive Account updates

Automate with triggers · Advanced · 20 min · Runs in your Salesforce Developer org · Apex Path

Scenario. A sync step must stamp each Account after it saves. The stamp is an update to the same Account, which runs the trigger again, so the handler must stop after one pass.

Stamp each updated Account once from an after-update trigger, and use a static Set of Ids to stop the update from running the trigger again and again.

What you will learn

In an after trigger, Trigger.new is read-only. To change those records you must update them, and that update runs the same trigger again. That is when you need a recursion guard: a static Set of the Ids you already handled.

if (handledIds.contains(row.Id)) {
    continue;
}
handledIds.add(row.Id);

Gotcha. If a before trigger can make the change, use it: no DML, no recursion. A static guard lasts the whole transaction, so it also skips a later update of the same record.

The task

Complete the handler so each updated Account gets :: synced added to its Description exactly once, using one follow-up update.

Examples:

• Description Start → Start :: synced
• blank Description → synced
• 200 Accounts updated together → each marked once, with one follow-up update

Requirements:

1. Skip any Account whose Id is already in handledIds. Add new Ids before you update.
2. Read Description from the records in records. They hold the values that were just saved.
3. Do not change records. They are read-only, so build new Account(Id = ..., Description = ...) for each one.
4. Add :: synced (space, two colons, space) when there is text. Use synced when it is blank.
5. Update the new Accounts once, after the loop.

Starter code

public class AS_F6172D398608_RecursionGuard {
    private static Set<Id> handledIds = new Set<Id>();

    public static void afterUpdate(List<Account> records) {
        List<Account> followUps = new List<Account>();
        for (Account account : records) {
        }
    }
}

When it passes

Each updated Account gets exactly one marker built from its new Description. The second trigger run is skipped, and 200 Accounts cost the same DML as one.

Try this drill free

You write the Apex yourself. ApexSensei runs it and tells you what passed and what did not.

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