Professional C# and .NET, 2021st Edition

21Entity Framework Core

WHAT'S IN THIS CHAPTER?

• Introducing Entity Framework Core
• Working with conventions, annotations, and the Fluent API
• Using queries, compiled queries, and global query filters
• Defining relationships with conventions, annotations, and the Fluent API
• Using table per hierarchy, table splitting, and owned entities
• Tracking objects
• Updating objects and object trees
• Handling conflicts with updates
• Using transactions
• Using migrations with the .NET CLI tools

CODE DOWNLOADS FOR THIS CHAPTER

The source code for this chapter is available on the book page at www.wiley.com. Click the Downloads link. The code can also be found at https://github.com/ProfessionalCSharp/ProfessionalCSharp2021 in the directory 2_Libs/EFCore. The code for this chapter is divided into the following major examples:

• Intro
• Models
• ScaffoldSample
• MigrationsSample
• Queries
• Relations
• LoadingRelatedData
• Tracking
• ConflictHandling-LastWins
• ConflictHandling-FirstWins
• Cosmos

Samples from this chapter mainly use the Micrsooft.EntityFrameworkCore, Microsoft.EntityFrameworkCore.SqlServer, and Micrsoft.Extensions.Hosting NuGet packages. All the sample projects have nullable reference types enabled.

INTRODUCING EF CORE

When you use ADO.NET directly, you can use a data reader such as SqlDataReader or SqliteDataReader to manually fill your objects with data from the database. With Entity Framework Core (EF Core), you don't need to write SQL statements because you get the mapping from relational ...