My motive behind asking this is, trying to understand the roles and responsibilities of each databases and differentiate them from the other database(Sitecore Experience Platform).
Sitecore Commerce 9 has 2 databases:
The Global database – stores all the global configuration data (policies and environments) that govern how the engine roles function.
The Shared Environments database – the main data store for a commerce deployment. It stores all of the commerce data used on site, including catalog data, customer records, pricing information, and any promotions you have configured, along with the generic entities and lists that power the functionality created in the various installed plugins.
There are two Databases which gets installed on installing Sitecore commerce 9
- Global DataBase : It Stores all the Global configuration data of Sitecore commerce Engine . Any Customization that needs to be done apart from generic commerce engine has to be done here.
Global configuration data can be Policies or environment A policy is a group of settings that define and affect the functionality of the individual features or plugins in the commerce engine.
Policies are named, versionable, variable datasets that help make the engine flexible and configurable. They are stored in the policy store in the Global database and are heavily cached.
An environment in Sitecore XC is a collection of policies that affect how a call to the engine is handled. In other words, when a storefront calls the commerce engine for any functionality, it identifies the appropriate environment, which in turn effects the functionality provided by the engine.
2.Shared Environment : It stores all of the commerce data which you create in commerce like your catalog , inventory , price Card, Promotions , customer details , order Details