Chapter 7 described how to configure scalar (nonrelational) properties. This chapter covers how to configure database relationships. I assume that you’ve read at least the first part of chapter 7, because configuring relationships uses the same three approaches—By Convention, Data Annotations, and the Fluent API—to map the database relationships.
This chapter covers how EF Core finds and configures relationships between entity classes, with pointers and examples showing how to configure each type of relationship: one-to-one, one-to-many, and many-to-many. EF Core’s By Convention relationship rules can configure many relationships quickly, but you’ll also learn about all the Data Annotations and Fluent API configuration options, which allow you to define precisely the way you want a relationship to behave. You’ll also look at features that allow you to enhance your relationships with extra keys and alternative table-mapping approaches. Finally, you’ll consider five ways to map your classes to the database.