Absolute Free Architecture-Specialist Exam Practice for Comprehensive Preparation 

Isolated Business Logic (Actions) or Core Widgets (blocks), to manage complexity, composition or to have its own lifecycle.

A BL becomes a Calculation Engine if it performs complex calculations, (e.g. an invoice calculation engine or an insurance simulator). Engines are usually subject to versions. 

Logic to Synchronize data in CS-s with an external system. Isolating this logic makes the CS completely system agnostic and it-s easier to decouple or replace the external system.

Technical wrapper to expose an API to External consumers, keeping core services system agnostic and supporting multiple versions of the API.

Discovery automatically assigns a module to an Architecture Canvas layer, following the module's naming convention. 

Discovery allows you to determine for every module, which elements are being consumed by other modules. 

Same as ECS with local replica but API module is provided. So any changes to the external system can notify OS, which OS then gets update from the ERP system (subscription system) 

... Entity is not in Outsystems but in an external ERP system. IS just makes remote call to p external system/database. No data is being kept inside OS. Data retrieval may not be optimized as it needs to traverse two different systems to get the information back. Con: Integration API must support all use cases

Same as ECS with local replica but synchronization logic is separated. Pro: Code independence. Consumers of CS is not affected by Sync. Sync can orchestrate several CS

... caches only summary data that is frequently lister, joined or searched. Full detail for a single entry is fetched directly from external system. Use when whole database too big or costly to synchronize. Details are only required for single entities (not lists) 

... Entity is exposed as read-only and API is available to centralize business logic for entity creation/update 

... a wrapper used to contain the logic, actions and data that will expose code that is inside of external library or to inspect external database and import the data structures so they can be used as entities inside of OS 

... is needed if data is coming from MULTIPLE external systems. IS will decide which driver to use depending on the data. 

... tries to fetch data from local cache entity, if not there, get single entry from the external n system. Cache only that record (read-through caching) Use when whole database too big or costly to synchronize. Integration only touches a small portion of the database. Avoid if access to lists of data is needed up front

... is a pattern with two modules, a connector module that can be used to encapsulate an ) external API with the input/output structures and a wrapper module to expose the normalized API to the consumers. 

Same as Base ECS pattern, but have a local replica. Store data to serve as a local cache. Pro: Leverage Entity Use, Simpler Integration API. Con: Less impact on source system