# Transactions, the save order and recursion

*Platform Developer Study Guide · Process Automation and Logic · Last updated October 15, 2026 · https://www.certifyforce.com/study-guide/platform-developer/process-automation-and-logic/transactions-order-of-execution-and-recursion*

How an Apex transaction commits or rolls back as one unit, where before-save flows, triggers and validation rules sit in the save order of execution, how DML and roll-up summaries cascade into more saves, and how savepoints and transaction-scoped static variables control rollback and recursion.

- Certification: Salesforce Platform Developer
- Exam section: Process Automation and Logic
- Study guide: https://www.certifyforce.com/study-guide/platform-developer

**Official exam objective:**

> Describe the relationship between Apex transactions, the save order of execution, and the potential for recursion and/or cascading.

## What the exam expects

- Predict what survives an unhandled exception in an Apex transaction.
- Place before-save flows, triggers, validation rules, roll-ups and the commit in the save order, and predict what a validation rule sees.
- Recognise cascading: DML, flows and roll-up summaries that send another record through its own save.
- Diagnose trigger recursion and choose the fix: move same-record updates before the save, or guard re-entry with a static variable.
- Use `Database.setSavepoint()` and `Database.rollback()`, and know their limits.

Key terms: **transaction** (operations that commit or roll back together); **save order of execution** (the fixed sequence Salesforce runs on insert, update or upsert); **cascading** (one save starting another record's save); **recursion** (automation re-firing because of its own DML); **savepoint** (a point you can roll the database back to).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Transaction failure | An error in any operation rolls back the entire transaction; nothing is committed | [Apex Transactions](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_transaction.htm) |
| When DML commits | Once, after roll-ups and criteria-based sharing, near the end of the save order | [Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm) |
| Before-save flow position | Immediately before Apex before triggers | [Before-Save Flows](https://help.salesforce.com/s/articleView?id=platform.flow_concepts_trigger_record.htm&type=5) |
| Custom validation rules | Run after before triggers, so they see values those triggers set | [Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm) |
| Modifying Trigger.new | Allowed only in before triggers; after-trigger records are read-only | [Trigger Context Variables](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_context_variables.htm), [Triggers](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers.htm) |
| Roll-up summary | Parent (and grandparent) records go through their own save procedure | [Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm) |
| Recursive save | Skips steps 9 (assignment rules) through 17 | [Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm) |
| Static variable scope | One transaction; persists across trigger invocations, reset for the next transaction | [Static and Instance Variables](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_classes_static.htm) |
| Savepoint cost | Counts toward the DML statement limit | [Transaction Control](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/langCon_apex_transaction_control.htm) |
| Rollback and statics | Static variables aren't reverted by a rollback | [Transaction Control](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/langCon_apex_transaction_control.htm) |

## Check yourself

- Why does a value set on Trigger.new in a before insert trigger need no DML statement?
- When does inserting a detail record fire triggers on its master?
- Why does a static Boolean in a helper class stop trigger recursion when an instance variable does not?
- Which savepoint becomes invalid when you roll back to SP1 after creating SP1 and then SP2?

## Sources

- [Triggers and Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm)
- [Apex Transactions](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_transaction.htm)
- [Transaction Control](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/langCon_apex_transaction_control.htm)
- [Static and Instance Methods, Variables, and Initialization Code](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_classes_static.htm)
- [Triggers](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers.htm)
- [Trigger Context Variables](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_context_variables.htm)
- [Exceptions in Apex](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_exception_definition.htm)
- [Bulk DML Exception Handling](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_dml_bulk_exceptions.htm)
- [Before-Save Record-Triggered Flows](https://help.salesforce.com/s/articleView?id=platform.flow_concepts_trigger_record.htm&type=5)
- [How Flows Run in Transactions](https://help.salesforce.com/s/articleView?id=platform.flow_concepts_transaction.htm&type=5)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 9 linked practice questions, and unlimited timed mock exams are included with the Platform Developer pack (USD $19): https://www.certifyforce.com/practice-exams