What can an aggregate not use as its source?

An aggregate in OutSystems is designed to perform queries on data, and it can source this data from various types of entities. However, static records are not considered a valid source for an aggregate.

Static records are immutable and predefined data points that remain constant; they do not change during the application execution and are typically not stored in the database. Aggregates, on the other hand, are dynamic and intended for retrieving, processing, and possibly displaying data that can change, depending on user interactions or other factors within the application.

Dynamic entities are those that can vary in structure or content at runtime, such as records pulled from a database or an API. Aggregates can source data from these dynamic entities effectively. Similarly, external systems can be leveraged to pull in data, and local entities, which are the ones defined within the application's own database, can also be queried by aggregates.

In summary, while aggregates can use various dynamic sources to pull data, they cannot utilize static records because those records do not allow for the dynamic querying and manipulation that aggregates are designed to perform.