警告

This documentation is for EF7 onwards. For EF6.x and earlier release see http://msdn.com/data/ef. 本文档是基于EF7版本.对于EF6.x及更早的版本请参见 http://msdn.com/data/ef.

注解

This article uses EF 7.0.0-rc1 which is the latest pre-release available on NuGet.org. You can find nightly builds of the EF7 code base hosted on https://www.myget.org/F/aspnetvnext/ but we do not maintain up-to-date documentation for nightly builds.

注解

The configuration in this section is applicable to relational databases in general. The extension methods shown here will become available when you install a relational database provider (due to the shared EntityFramework.Relational package).

Foreign Key Constraints

A foreign key constraint is introduced for each relationship in the model.

Conventions

By convention, foreign key constraints are named FK_<dependent type name>_<principal type name>_<foreign key property name>. For composite foreign keys <foreign key property name> becomes an underscore separated list of foreign key property names.

Data Annotations

Foreign key constraint names cannot be configured using data annotations.

Fluent API

You can use the Fluent API to configure the foreign key constraint name for a relationship.

    class MyContext : DbContext
    {
        public DbSet<Blog> Blogs { get; set; }
        public DbSet<Post> Posts { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Post>()
                .HasOne(p => p.Blog)
                .WithMany(b => b.Posts)
                .HasForeignKey(p => p.BlogId)
                .HasConstraintName("ForeignKey_Post_Blog");
        }
    }

    public class Blog
    {
        public int BlogId { get; set; }
        public string Url { get; set; }

        public List<Post> Posts { get; set; }
    }

    public class Post
    {
        public int PostId { get; set; }
        public string Title { get; set; }
        public string Content { get; set; }

        public int BlogId { get; set; }
        public Blog Blog { get; set; }