实体与许多一对多的关系创建升级到RC失败后， [英] Entity with many-to-many relationship creation fails after upgrading to RC

问题描述

我有3个简单的表项目，一对夫妇POCO类，并与代码，没有EDML文件创建的DbContext。用下面的代码设置与实体框架代码优先，我编辑的DbContext代码的测试工作，因为模型构建器从公测改为RC

I've got a project with 3 simple tables, a couple of POCO classes, and a DBContext created with code, no edml file. The following code setup used to work with the beta of Entity Framework code-first, I've edited the DbContext code since the ModelBuilder changed from the beta to RC

表（简单的表格很多一对多表有声明为级联删除外键）字段：

Tables (simple tables many-to-many table has fields declared as foreign keys with cascade deletion):

CREATE TABLE [dbo].[Bookings](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [StartDate] [datetime] NOT NULL,
    [EndDate] [datetime] NOT NULL,
    [AccountId] [varchar](50) NOT NULL,
 CONSTRAINT [PK_Bookings] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)

CREATE TABLE [dbo].[Units](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [Name] [nvarchar](100) NOT NULL,
    [Description] [nvarchar](1000) NULL,
    [Beds] [int] NOT NULL,
 CONSTRAINT [PK_Units] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)

CREATE TABLE [dbo].[UnitBookings](
    [UnitId] [int] NOT NULL,
    [BookingId] [int] NOT NULL
) ON [PRIMARY]

POCOS：

public class Unit
{
    [Key]
    public int ID { get; set; }
    [Required]
    public string Name { get; set; }
    public string Description { get; set; }
    [Required]
    public int Beds { get; set; }
    public ICollection<Booking> Bookings { get; set; }
}

public class Booking
{
    [Key]
    public int ID { get; set; }
    [Required]
    public DateTime StartDate { get; set; }
    [Required]
    public DateTime EndDate { get; set; }
    [Required]
    public string AccountId { get; set; }
    public ICollection<Unit> Units { get; set; }
}

DB上下文

DB Context

public class BookingDb : DbContext
{
    public DbSet<Booking> Bookings { get; set; }
    public DbSet<Unit> Units { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Unit>()
            .HasMany(u => u.Bookings)
            .WithMany(b => b.Units)
            .Map(m => m.MapLeftKey("BookingId").MapRightKey("UnitId").ToTable("UnitBookings"));
    }
}

创建的预订（该bookingCarrrier是提供一个辅助类由前端层）

Creating a Booking (the bookingCarrrier is a helper class delivered by frontend layer)

public static bool CreateBooking(BookingCarrier carrier, out string statusMsg)
{
    using (var db = new BookingDB())
    {
        var validator = new BookingValidator(2, 3);
        Booking booking = CreateBooking(carrier, db);
        if (validator.Validate(booking.AccountId, booking, -1, out statusMsg)
        {
            db.Bookings.Add(booking);
            db.SaveChanges();
            return true;
        }
        return false;
    }
}

private static CreateBooking(BookingCarrier carrier, BookingDB db)
{
    var units = new List<Unit>();
    if (carrier.SelectedUnit == 0)
        units.AddRange(db.Units.ToList());
    else
        units.Add(db.Units.Find(carrier.SelectedUnit));
    return new Booking
        {
            AccountId = carrier.AccountId,
            EndDate = carrier.EndDate,
            StartDate = carrier.StartDate,
            Units = units
        };
}

在执行这段代码，EF抛出具有以下消息的SQLException：

When executing this code, EF throws a SqlException with the following message:

INSERT语句冲突与
外键约束
FK_UnitBookings_Units。冲突
发生于数据库grashult.dk，
表dbo.Units，列ID。

The INSERT statement conflicted with the FOREIGN KEY constraint "FK_UnitBookings_Units". The conflict occurred in database "grashult.dk", table "dbo.Units", column 'ID'.

这是不是在测试的情况。

Which wasn't the case in the beta.

我知道这是一个相当简单的设置，但由于这是一个爱好项目，我想它怎么看简单的像这样的事情可以做的。

I know this is a fairly simplistic setup, but since this a hobby project, and I'm trying it out to see how simple a thing like this can be done.

是谁认识的变化导致此行为？是这样仍然可以使用EF 4.1，或者我必须马上拿出数据模型设计？

Are anybody aware of changes that causes this behaviour? Is something like this still possible with EF 4.1, or do I have to whip out the data model designer?

问候
加斯帕豪格

Regards Jesper Hauge

推荐答案

您必须交换密钥映射：

modelBuilder.Entity<Unit>()
            .HasMany(u => u.Bookings)
            .WithMany(b => b.Units)
            .Map(m => m.MapLeftKey("UnitId")
                       .MapRightKey("BookingId")
                       .ToTable("UnitBookings"));

我只是测试它，问题是， Booking.Id 保存在 UnitId 和 UnitId 在 Booking.Id 。

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