使用Fluent API的EF核心中的一对一关系[副本]

正如其他答案所指出的,关键是使用 HasForeignKey<>() 配置外键的方法。

但是要小心,应该在依赖实体而不是主体实体上设置外键。

具体操作方法:

将导航属性添加到 Course 对于 Customer

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
    public Course Course {get;set;} 
}

现在设置 Course.Id 作为一个 FK 它引用了 Customer.Id

public class AppDbContext : DbContext
{
    public AppDbContext (DbContextOptions<AppDbContext> options)
        : base(options)
    {
    }
    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);

        builder.Entity<Customer>(entity=>
        {
            entity.HasOne(customer=>customer.Course)
                .WithOne(course=> course.Customer)
                .HasForeignKey<Course>(course=>course.Id); 
        });
    }

    public DbSet<App.Models.Customer> Customer { get; set; }
    public DbSet<App.Models.Course> Courses{ get; set; }
}

生成的SQL脚本是:

CREATE TABLE [Customer] (
    [Id] int NOT NULL IDENTITY,
    [Name] nvarchar(max) NULL,
    CONSTRAINT [PK_Customer] PRIMARY KEY ([Id])
);

GO

CREATE TABLE [Courses] (
    [Id] int NOT NULL,
    [CouseName] nvarchar(max) NULL,
    CONSTRAINT [PK_Courses] PRIMARY KEY ([Id]),
    CONSTRAINT [FK_Courses_Customer_Id] FOREIGN KEY ([Id]) REFERENCES [Customer] ([Id]) ON DELETE CASCADE
);

GO

下面类似的内容应该会有所帮助。hasone方法与with one链接将有助于建立一对一关系:

public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }

}

public class Course
{
    public int Id { get; set; }
    public string CourseName { get; set; }
    public int CustomerId {get;set;}
    public virtual Customer Customer { get; set; }
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Course>()
        .HasOne(a => a.Customer)
        .WithOne(b => b.Course)
        .HasForeignKey<Course>(b => b.CustomerId);
}