In this blogpost explains how to configure entities using Fluent API of Entity Framework Core or EF6 above versions for the Code First approach. This will give you details about how to configure business rules with Fluent API methods for PrimaryKey, Unique, Index, Required, Identity, etc.
Fluent API is used to configure data models to override conventions. It is based on the Fluent API design pattern where results are captured using method chaining.
You can configure data models using Data Annotations or Fluent API. Data Annotations gives the only subset of configurations, Fluent API provides full set of configuration options available for code first.
- DataModels folder has models with Fluent API used.
For more details about Fluent API configuration click here