Change Data Capture Developer Guide

Change Data Capture
Keep Your External Data Current with Change Data Capture
Change Event Message Structure
Merged Change Events
Other Types of Change Events: Gap and Overflow Events
Subscribe to Change Events
Change Event Storage and Delivery
Subscription Channels
Compose Streams of Change Data Capture Notifications with Custom Channels
Example Diagrams for Channels and Channel Members
High-Level Replication Steps
Subscribe with CometD Using the EMP Connector Sample
Enrich Change Events with Extra Fields When Subscribed with CometD
Subscribe with Apex Triggers
Change Event Triggers
Apex Trigger Quick Start
Apex Trigger Example
Test Change Event Triggers
Change Event Trigger Considerations
Obtain Apex Trigger Subscribers
Monitor Change Event Publishing and Delivery Usage
Security Considerations
Change Event Considerations
Standard Object Notes
Change Events for Fields
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Apex Trigger Example

This sample trigger demonstrates a common use for change event triggers and provides a more complex trigger example than the quick start.

Using an Apex Change Event Trigger to Predict Account Status

Because Apex change event triggers run asynchronously, they typically contain time-intensive processes that run after the database transaction is completed. This trigger example covers a more common real-world scenario than the trigger given in the quick start. It captures case changes and predicts the account trust status using an Apex class. The prediction is based on counting the account cases and checking case fields. In other scenarios, you might have complex prediction algorithms that are more resource intensive.

The trigger calls a method in an Apex class to perform the trust prediction on the accounts related to all cases in this trigger. An account status of Red means that the account trust level is low because too many cases are associated with this account among other criteria. An account status of Green means that the trust level is good. The associated class is listed after this trigger. This example assumes that you have the following prerequisites.
  • A platform event named Red_Account__e with two fields: Account_Id__c of type Text and Rating__c of type Text
  • The SLAViolation__c custom field on the Case object of type Picklist with values Yes and No

The RedAccountPredictor class performs the prediction of the account trust level. The first method that the trigger calls is predictForCases, which calls other methods in this class. The method returns a map of account ID to a Boolean value for account status.