What is the trigger.new?

Insert, update and undelete only; editable only in before triggers.

What is the trigger.newMap?

Before update, after insert, after update, after undelete.

What is the trigger.old and oldMap?

Update and delete only; always read-only.

What is DML on trigger collections?

Trigger.new and Trigger.old can't be used in DML.

Delete events for losers, update events for the winner; no merge event.

What is the masterRecordId?

Set on losing records only in after delete.

What is the addError in delete triggers?

Call it on Trigger.old records.

What is the chunk size?

Trigger invoked per 200-record batch; Trigger.size counts the batch only.

Process Automation, Logic, and Integration27% of the exam

Advanced trigger context and handler patterns

Which trigger context variables exist in each event, how merge and undelete fire triggers, how addError blocks saves and deletes, and how a single trigger with a handler, bulk-safe code and Id-based recursion guards survives 200-record chunks.

Official exam objective

Demonstrate knowledge of the best practices for writing Apex triggers.

~7 min read · 10 practice questions · updated Oct 16, 2026

What the exam expects

Read trigger code and spot a context variable used in an event where it is null or read-only (Trigger.new in delete, Trigger.newMap in before insert, editing Trigger.new after save).
Route logic to the exact event with Trigger.operationType instead of isInsert alone.
Predict which triggers fire on merge and undelete, and where MasterRecordId is readable.
Block a save or delete with addError() on the right collection.
Apply the trigger standards: one trigger per object with handlers, bulk-safe SOQL and DML, asynchronous callouts, and recursion guards that work across 200-record chunks.

Key terms: context variable (an implicit System.Trigger member such as new, oldMap or operationType); handler (the class a trigger delegates to); recursion guard (state that stops logic re-running in one transaction); chunk (a 200-record batch that gets its own trigger invocation); losing record (a record deleted by a merge).

Key facts

Fact	Detail	Source
Trigger.new	Insert, update and undelete only; editable only in before triggers	Trigger Context Variables (opens in a new tab)
Trigger.newMap	Before update, after insert, after update, after undelete	Trigger Context Variables (opens in a new tab)
Trigger.old and oldMap	Update and delete only; always read-only	Context Variable Considerations (opens in a new tab)
DML on trigger collections	Trigger.new and Trigger.old can't be used in DML	Context Variable Considerations (opens in a new tab)
Merge	Delete events for losers, update events for the winner; no merge event	Triggers and Merge Statements (opens in a new tab)
MasterRecordId	Set on losing records only in after delete	Triggers and Merge Statements (opens in a new tab)
addError in delete triggers	Call it on Trigger.old records	Trigger Exceptions (opens in a new tab)
Chunk size	Trigger invoked per 200-record batch; Trigger.size counts the batch only	Trigger Context Variables (opens in a new tab)
Between Bulk API chunks	Limits reset; static variables don't	Static Variables (opens in a new tab)
DML statement limit	150 per transaction	Governor Limits (opens in a new tab)

Trigger.new

Detail: Insert, update and undelete only; editable only in before triggers
Source: Trigger Context Variables (opens in a new tab)

Trigger.newMap

Detail: Before update, after insert, after update, after undelete
Source: Trigger Context Variables (opens in a new tab)

Trigger.old and oldMap

Detail: Update and delete only; always read-only
Source: Context Variable Considerations (opens in a new tab)

DML on trigger collections

Detail: Trigger.new and Trigger.old can't be used in DML
Source: Context Variable Considerations (opens in a new tab)

Merge

Detail: Delete events for losers, update events for the winner; no merge event
Source: Triggers and Merge Statements (opens in a new tab)

MasterRecordId

Detail: Set on losing records only in after delete
Source: Triggers and Merge Statements (opens in a new tab)

addError in delete triggers

Detail: Call it on Trigger.old records
Source: Trigger Exceptions (opens in a new tab)

Chunk size

Detail: Trigger invoked per 200-record batch; Trigger.size counts the batch only
Source: Trigger Context Variables (opens in a new tab)

Between Bulk API chunks

Detail: Limits reset; static variables don't
Source: Static Variables (opens in a new tab)

DML statement limit

Detail: 150 per transaction
Source: Governor Limits (opens in a new tab)

Sources for this section (6)

Check yourself

Why does `Trigger.newMap` throw a NullPointerException in a before insert trigger?
When can a trigger read a losing record's MasterRecordId?
Why does a static Boolean guard skip records after the first 200 in a Bulk API load?
Which collection do you call addError() on to block a delete?

The questions are free to read. Answers with their sources and self-grading are included with the pack.

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What the exam expects

Key facts

Check yourself

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