When a record is saved with an insert, update, or upsert statement, the following events occur in order:
  1. The original record is loaded from the database or initialized for in case of an insert statement.
  2. The new record field values are loaded from the request and overwrite the old values.
  3. System validation occurs, such as verifying that all required fields have a non-null value, and running any user-defined validation rules.
  4. All before triggers execute.
  5. The record is saved to the database, but not yet committed.
  6. All after triggers execute.
  7. Assignment rules execute.
  8. Auto-response rules execute.
  9. Workflow rules execute.
  10. If there are workflow field updates, the record is updated again.
  11. If the record was updated with workflow field updates, before and after triggers fire one more time (and only one more time).
  12. Escalation rules execute.
  13. All DML operations are committed to the database.
  14. Post-commit logic executes, such as sending email.
Here is the diagram –

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It is always important to keep the order of execution in mind. Please provide your feedback.