A business practitioner is creating three different activities:
1) Targeting a recipient with a specific email domain
2) Targeting recipients that are over 30 years old
3) Targeting deliveries with a delivery status equal to failed
The business practitioner attempts to combine the three results using the "Union" activity, and they receive the following error: "The document types of inbound events are incompatible (step 'Union'). Unable to perform the operation."
What is the cause for the error in the union activity?
The error in the 'Union' activity is caused by the attempt to combine results from activities with different targeting dimensions. The Union activity requires that all incoming transitions (the populations to be combined) have the same schema structure. In this case, targeting recipients based on email domain and age involves recipient attributes, which are usually part of the same recipient schema. However, targeting based on delivery status involves attributes from the delivery schema. Since these schemas have different structures and fields, the Union activity cannot combine them directly without configuration that reconciles these differences. Reference: The answer is based on the principles of database schema structures and the functionality of union operations within data processing workflows, as typically encountered in campaign management systems like Adobe Campaign Classic.