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Der folgende Test wurde mit SQL Server und SqlClient durchgeführt als Anbieter. Die Tatsache, dass das Problem mit SQL Server nicht reproduzierbar ist, wirft die Frage auf, ob die MySql Anbieter, den Sie verwenden, weist einen Fehler auf, der falsches SQL für Ihre LINQ-Abfrage erstellt. Es sieht aus wie das gleiche Problem wie in dieser Frage
wo das Problem mit einem MySql aufgetreten ist Anbieter und konnte mit SqlClient nicht reproduziert werden /SQL-Server.
Ich habe das fettgedruckte Beispiel (mit EF 4.3.1) getestet und kann das Problem nicht reproduzieren:
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
namespace EFInclude
{
public class Harbor
{
public int HarborId { get; set; }
public virtual ICollection<Ship> Ships { get; set; }
public string Description { get; set; }
}
public class Ship
{
public int ShipId { get; set; }
public int HarborId { get; set; }
public virtual Harbor Harbor { get; set; }
public virtual ICollection<CrewMember> CrewMembers { get; set; }
public string Description { get; set; }
}
public class CrewMember
{
public int CrewMemberId { get; set; }
public int ShipId { get; set; }
public virtual Ship Ship { get; set; }
public int RankId { get; set; }
public virtual Rank Rank { get; set; }
public int ClearanceId { get; set; }
public virtual Clearance Clearance { get; set; }
public string Description { get; set; }
}
public class Rank
{
public int RankId { get; set; }
public virtual ICollection<CrewMember> CrewMembers { get; set; }
public string Description { get; set; }
}
public class Clearance
{
public int ClearanceId { get; set; }
public virtual ICollection<CrewMember> CrewMembers { get; set; }
public string Description { get; set; }
}
public class MyContext : DbContext
{
public DbSet<Harbor> Harbors { get; set; }
public DbSet<Ship> Ships { get; set; }
public DbSet<CrewMember> CrewMembers { get; set; }
public DbSet<Rank> Ranks { get; set; }
public DbSet<Clearance> Clearances { get; set; }
}
class Program
{
static void Main(string[] args)
{
Database.SetInitializer(new DropCreateDatabaseAlways<MyContext>());
using (var context = new MyContext())
{
context.Database.Initialize(true);
var harbor = new Harbor
{
Ships = new HashSet<Ship>
{
new Ship
{
CrewMembers = new HashSet<CrewMember>
{
new CrewMember
{
Rank = new Rank { Description = "Rank A" },
Clearance = new Clearance { Description = "Clearance A" },
Description = "CrewMember A"
},
new CrewMember
{
Rank = new Rank { Description = "Rank B" },
Clearance = new Clearance { Description = "Clearance B" },
Description = "CrewMember B"
}
},
Description = "Ship AB"
},
new Ship
{
CrewMembers = new HashSet<CrewMember>
{
new CrewMember
{
Rank = new Rank { Description = "Rank C" },
Clearance = new Clearance { Description = "Clearance C" },
Description = "CrewMember C"
},
new CrewMember
{
Rank = new Rank { Description = "Rank D" },
Clearance = new Clearance { Description = "Clearance D" },
Description = "CrewMember D"
}
},
Description = "Ship CD"
}
},
Description = "Harbor ABCD"
};
context.Harbors.Add(harbor);
context.SaveChanges();
}
using (var context = new MyContext())
{
DbSet<Harbor> dbSet = context.Set<Harbor>();
IQueryable<Harbor> query = dbSet;
query = query.Include(entity => entity.Ships);
query = query.Include(entity => entity.Ships.Select(s => s.CrewMembers));
query = query.Include(entity => entity.Ships.Select(s => s.CrewMembers.Select(cm => cm.Rank)));
query = query.Include(entity => entity.Ships.Select(s => s.CrewMembers.Select(cm => cm.Clearance)));
var sqlString = query.ToString();
// see below for the generated SQL query
var harbor = query.Single();
Console.WriteLine("Harbor {0} Description = \"{1}\"",
harbor.HarborId, harbor.Description);
foreach (var ship in harbor.Ships)
{
Console.WriteLine("- Ship {0} Description = \"{1}\"",
ship.ShipId, ship.Description);
foreach (var crewMember in ship.CrewMembers)
{
Console.WriteLine("-- CrewMember {0} Description = \"{1}\"",
crewMember.CrewMemberId, crewMember.Description);
Console.WriteLine("-- CrewMember {0} Rank Description = \"{1}\"",
crewMember.CrewMemberId, crewMember.Rank.Description);
Console.WriteLine("-- CrewMember {0} Clearance Description = \"{1}\"",
crewMember.CrewMemberId, crewMember.Clearance.Description);
}
}
Console.ReadLine();
}
}
}
}
Die Ausgabe ist:
Laut Ihrer Beschreibung in Fettdruck sollte ich haben:CrewMember 1 Description ="Rank A" und das gleiche Durcheinander für die anderen 3 Besatzungsmitglieder. Aber das habe ich nicht.
Ist etwas in meinem Testprogramm anders als in Ihrem Code, wo Sie den Fehler haben?
Bearbeiten
Das generierte SQL für die Abfrage (siehe Zeile var sqlString = query.ToString(); Im obigen Quellcode ist das Folgende der Inhalt von sqlString ) ist:
SELECT
[Project1].[HarborId] AS [HarborId],
[Project1].[Description] AS [Description],
[Project1].[C2] AS [C1],
[Project1].[ShipId] AS [ShipId],
[Project1].[HarborId1] AS [HarborId1],
[Project1].[Description1] AS [Description1],
[Project1].[C1] AS [C2],
[Project1].[CrewMemberId] AS [CrewMemberId],
[Project1].[ShipId1] AS [ShipId1],
[Project1].[RankId] AS [RankId],
[Project1].[ClearanceId] AS [ClearanceId],
[Project1].[Description2] AS [Description2],
[Project1].[RankId1] AS [RankId1],
[Project1].[Description3] AS [Description3],
[Project1].[ClearanceId1] AS [ClearanceId1],
[Project1].[Description4] AS [Description4]
FROM ( SELECT
[Extent1].[HarborId] AS [HarborId],
[Extent1].[Description] AS [Description],
[Join3].[ShipId1] AS [ShipId],
[Join3].[HarborId] AS [HarborId1],
[Join3].[Description1] AS [Description1],
[Join3].[CrewMemberId] AS [CrewMemberId],
[Join3].[ShipId2] AS [ShipId1],
[Join3].[RankId1] AS [RankId],
[Join3].[ClearanceId1] AS [ClearanceId],
[Join3].[Description2] AS [Description2],
[Join3].[RankId2] AS [RankId1],
[Join3].[Description3] AS [Description3],
[Join3].[ClearanceId2] AS [ClearanceId1],
[Join3].[Description4] AS [Description4],
CASE WHEN ([Join3].[ShipId1] IS NULL) THEN CAST(NULL AS int) WHEN ([Join3].[CrewMemberId] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C1],
CASE WHEN ([Join3].[ShipId1] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C2]
FROM [dbo].[Harbors] AS [Extent1]
LEFT OUTER JOIN (SELECT [Extent2].[ShipId] AS [ShipId1], [Extent2].[HarborId] AS [HarborId], [Extent2].[Description] AS [Description1], [Join2].[CrewMemberId], [Join2].[ShipId2], [Join2].[RankId1], [Join2].[ClearanceId1], [Join2].[Description2], [Join2].[RankId2], [Join2].[Description3], [Join2].[ClearanceId2], [Join2].[Description4]
FROM [dbo].[Ships] AS [Extent2]
LEFT OUTER JOIN (SELECT [Extent3].[CrewMemberId] AS [CrewMemberId], [Extent3].[ShipId] AS [ShipId2], [Extent3].[RankId] AS [RankId1], [Extent3].[ClearanceId] AS [ClearanceId1], [Extent3].[Description] AS [Description2], [Extent4].[RankId] AS [RankId2], [Extent4].[Description] AS [Description3], [Extent5].[ClearanceId] AS [ClearanceId2], [Extent5].[Description] AS [Description4]
FROM [dbo].[CrewMembers] AS [Extent3]
INNER JOIN [dbo].[Ranks] AS [Extent4] ON [Extent3].[RankId] = [Extent4].[RankId]
LEFT OUTER JOIN [dbo].[Clearances] AS [Extent5] ON [Extent3].[ClearanceId] = [Extent5].[ClearanceId] ) AS [Join2] ON [Extent2].[ShipId] = [Join2].[ShipId2] ) AS [Join3] ON [Extent1].[HarborId] = [Join3].[HarborId]
) AS [Project1]
ORDER BY [Project1].[HarborId] ASC, [Project1].[C2] ASC, [Project1].[ShipId] ASC, [Project1].[C1] ASC
