Apex Triggers Explained Series

Introduction

• Topic: Apex Triggers
• Format: Explained Series (30 videos)
• Purpose: Understand, use cases (30 examples), decision making for triggers
• Goals: Before/After context, use cases, decision process

Basics of Apex Triggers

• Definition: Custom actions before/after changes to Salesforce records (insert, update, delete)
• Example Scenarios: Notifications, emails, validation, complex logic handling
• Record Handling: Bulk triggers (handle multiple records)
• Limitations: Read-only in some contexts, insertion, updates, before/after events

Use Cases Where Triggers are Ideal

• Complex Logic: Hard to manage with flow/process builders, custom handling
• Before Events: Validation, additional values
• Exception Handling: User-friendly error messages
• Delete and Undelete: Handle deletion/restoration of records
• Partial Success: Allows some transactions to succeed despite errors

Syntax and Creation

• Key Components: Trigger keyword, trigger name, object, events
• Events: Comma-separated list (before insert, after insert, before update, etc.)
• Example: trigger AccountTrigger on Account (before insert, after update) { /* code */ }
• Procedure: Developer Console -> New -> Apex Trigger -> Enter details

Context Variables

• Types:
  • trigger.isInsert, trigger.isUpdate, trigger.isDelete
  • trigger.isBefore, trigger.isAfter
  • trigger.new, trigger.old, trigger.newMap, trigger.oldMap
  • trigger.size
• Usage: Determine current context, handle different events, debugging

Order of Execution

1. Load Record: Old values loaded, new values overwrite
2. Validation: Checks for integrity, required fields, custom rules
3. Before Triggers: Executes before triggers defined
4. After Triggers: Executes after triggers defined
5. Parent Updates: Updates roll-up summaries, cross-object rules
6. Commit: Finalize transaction, execute asynchronous notifications

Best Practices

• One Trigger Per Object: Avoid multiple triggers for same object/event for predictable order
• Code Maintenance: Simplify debugging, upfront planning
• Example: Use flags and context variables to segregate logic within a single trigger file

Deciding Between Before/After Triggers

• Before Triggers: Set additional values, validate data, prevent bad data
• After Triggers: Post-processing logic, create related records, send notifications

Context Grid

• Purpose: Shows which context variables are available in different events
• Values:
  • trigger.new not available in delete
  • trigger.old only for update/delete
  • trigger.newMap and trigger.oldMap available in specific contexts

Conclusion

• Next Steps: Upcoming 30 use cases
• Engagement: Encouragement to follow along, practice alongside
• Resources: Grid preparation for understanding different contexts

See you in the next video with the first use case!