The Common Data Service (now Microsoft Dataverse) is the correct component. Dataverse is a scalable data service and app platform that allows you to securely store and manage data from multiple sources. In this scenario, you can bring the data from the old point-of-sale (POS) system into custom tables within Dataverse. You can then create relationships between this imported data and the standard tables used by Dynamics 365 Commerce, such as 'Account' and 'Product', which also reside in Dataverse. This creates a unified data model that the Power Apps app can use to display the linked information.

A. business process flow: This guides users through a predefined business process. It does not store or integrate data from external systems.

B. business rule: This applies logic to data within Dataverse tables, such as validating data or showing/hiding fields. It is not used for data integration.

D. entity metadata: This defines the structure and behavior of a table (entity) in Dataverse, but it is not the data storage and integration service itself.

1. Microsoft Learn. (2023). What is Microsoft Dataverse? Microsoft Docs. "Dataverse allows data to be integrated from multiple sources into a single store

which can then be used in Power Apps

Power Automate

Power BI

and Power Virtual Agents along with data that's already available from the Dynamics 365 applications." (Section: "Why use Dataverse?").

2. Microsoft Learn. (2023). Tables in Dataverse. Microsoft Docs. "The tables within Dataverse are a foundational element and allow for the creation of a data model for your data. [...] Dynamics 365 apps

such as Dynamics 365 Sales

Customer Service

or Talent

also use the tables in Dataverse to store and secure data." (Section: "Introduction").

3. Microsoft Learn. (2023). Business process flows overview. Microsoft Docs. "A business process flow provides a guide for people to get work done. They provide a streamlined user experience that leads people through the processes their organization has defined for interactions that need to be advanced to a conclusion of some kind." (Section: "Why use business process flows?").

4. Microsoft Learn. (2023). Create a business rule for a table. Microsoft Docs. "You can create business rules and recommendations to apply logic and validations without writing code or creating plug-ins." (Section: "Create a business rule").