CDS is a relatively new paradigm created by Microsoft. It describes a storage mechanism for data in the cloud. This data is to be used and shared across multiple business applications.
CDS is currently at the core of Dynamics 365. The entire former CRM stack, now comprising of separate applications for Sales, Customer Service, Marketing, Field Service, and PSA, share the same CDS.
Within CDS, data is stored in a set of entities. From a programming perspective, you can think of comparing it to classes. Each entity represents an object type. Some common entities are Account, Contact, Lead, and so on.
You can think of entities as tables in a database or sheets in an Excel spreadsheet. The entity defines the model, the columns of the table. The individual records make up the data stored in these entities.
While CDS includes some standard entities that are typically used and shared across multiple applications, you can always create your new custom entities.
The licensing...