Question

我已经使用SqlLite .NET提供程序在Chinook数据库上成功设置了EF6。

现在，播放列表和曲目是通过联结表PlaylistTracks映射的多对多关系。

以下查询生成错误的SQL语句，其中Track被映射到联结表上的PlaylistId（它应该是TrackId）。

var result = context.Playlists
                    .Where(p => p.Name == "Brazilian Music")
                    .SelectMany(pt => pt.PlaylistTracks)
                    .Include(pt => pt.Track).OrderBy(pt => pt.TrackId);

SQL跟踪：

SELECT 
[Extent1].[PlaylistId] AS [PlaylistId], 
[Extent2].[PlaylistId] AS [PlaylistId1], 
[Extent2].[TrackId] AS [TrackId], 
[Extent3].[TrackId] AS [TrackId1], 
[Extent3].[Name] AS [Name], 
[Extent3].[AlbumId] AS [AlbumId], 
[Extent3].[MediaTypeId] AS [MediaTypeId], 
[Extent3].[GenreId] AS [GenreId], 
[Extent3].[Composer] AS [Composer], 
[Extent3].[Milliseconds] AS [Milliseconds], 
[Extent3].[Bytes] AS [Bytes], 
[Extent3].[UnitPrice] AS [UnitPrice]
FROM   [Playlist] AS [Extent1]
INNER JOIN [PlaylistTrack] AS [Extent2] ON [Extent1].[PlaylistId] = [Extent2].[PlaylistId]
INNER JOIN [Track] AS [Extent3] ON [Extent2].[PlaylistId] = [Extent3].[TrackId]
WHERE 'Brazilian Music' = [Extent1].[Name]
ORDER BY [Extent2].[TrackId] ASC

在最后一次INNER JOIN结束的某个地方我得到了

[Extent2]。[PlaylistId] = [Extent3]。[TrackId]

它应该是[Extent2]。[TrackId] = [Extent3]。[TrackId]其中[Extent2]是联结表。

如何让EF6映射到正确的外键？

感谢任何帮助。

看我原来的问题 Linq query returns the same names even though they should be different

以下是我配置POCO的方法

[DebuggerDisplay("{Name} (PlaylistId = {PlaylistId})")]
public class Playlist
{
    [Key]
    public int PlaylistId { get; set; }

    [Required, MaxLength(120)]
    public string Name { get; set; }

    [ForeignKey("TrackId")]
    public virtual ICollection<PlaylistTrack> PlaylistTracks { get; set; }
}

[DebuggerDisplay("{Name} (TrackId = {TrackId})")]
public class Track
{
    [Key]
    public int TrackId { get; set; }

    [Required, MaxLength(200)]
    public string Name { get; set; }

    public int? AlbumId { get; set; }

    [Required]
    public int MediaTypeId { get; set; }

    public int? GenreId { get; set; }

    [MaxLength(220)]
    public string Composer { get; set; }

    [Required]
    public int Milliseconds { get; set; }

    public int Bytes { get; set; }

    [Required]
    public decimal UnitPrice { get; set; }

    [ForeignKey("AlbumId")]
    public virtual Album Album { get; set; }

    [ForeignKey("GenreId")]
    public virtual Genre Genre { get; set; }

    [ForeignKey("MediaTypeId")]
    public virtual MediaType MediaType { get; set; }

    [ForeignKey("InvoiceLineId")]
    public virtual ICollection<InvoiceLine> InvoiceLines { get; set; }

    [ForeignKey("PlaylistId")]
    public virtual ICollection<PlaylistTrack> PlaylistTracks { get; set; }
}

[DebuggerDisplay("PlaylistId = {PlaylistId}, TrackId = {TrackId}")]
public class PlaylistTrack
{
    [Key, Column(Order = 1)]
    public int PlaylistId { get; set; }

    [Key, Column(Order = 2)]
    public int TrackId { get; set; }

    [ForeignKey("PlaylistId")]
    public virtual Playlist Playlist { get; set; }

    [ForeignKey("TrackId")]
    public virtual Track Track { get; set; }

}

Answer 1

好的，我修好了。我弄乱了关系映射。

曲目和播放列表应如下所示：

public class Track
{
  ...
  [ForeignKey("TrackId")]
  public virtual ICollection<PlaylistTrack> PlaylistTracks { get; set; }
}

public class Playlist
{
  ...
  [ForeignKey("PlaylistId")]
  public virtual ICollection<PlaylistTrack> PlaylistTracks { get; set; }
}

干杯

急切加载时EF6使用了错误的密钥

1 个答案: