Principles

Generic domain function should not be tightly coupled as another domain's service repository method

• Should instead be called as a field in the resolver layer

Layers

Presentation Layer

Handles the user interface and user interactions, presenting information to users and capturing user input

Business-Logic Layer

Intermediate between Presentation and Data Access layers.

This layer handles business logic, business rule, and calculations.

• Defines how data from the database can be retrieved and used, what it can perform, and cannot perform.
• Repsonsible for processing and manipulating data before it is presented to the user or stored in the database.
• Run validation to ensure that data meets business rules and constraints.
• Enforce business rules and policies like access control, authorization, and authentication.

Database Layer

Stores, maintains, and manages data structurally and organizationally