Common Data Service (CDS) for Apps lets you securely store and manage data that's used by business applications. Data within CDS for Apps is stored within a set of entities. An entity is a set of records used to store data, similar to how a table stores data within a database. CDS for Apps includes a base set of standard entities that cover typical scenarios, but you can also create custom entities specific to your organization and populate them with data using Power Query. App makers can then use PowerApps to build rich applications using this data.