Upravit
Níže uvedený test byl proveden pomocí serveru SQL Server a SqlClient jako poskytovatel. Skutečnost, že problém není reprodukovatelný pomocí SQL Serveru, vyvolává otázku, zda MySql poskytovatel, kterého používáte, má chybu, která vytváří nesprávné SQL pro váš dotaz LINQ. Vypadá to na stejný problém jako v této otázce
kde se vyskytl problém s MySql poskytovatele také a nelze jej reprodukovat pomocí SqlClient /SQL Server.
Testoval jsem příklad tučně (s EF 4.3.1) a nemohu problém zopakovat:
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();
}
}
}
}
Výstup je:
Podle vašeho popisu zvýrazněného tučně bych měl mít:Popis člena posádky 1 ="Pořadí A" a stejný nepořádek pro další 3 členy posádky. Ale tohle nemám.
Liší se něco v mém testovacím programu ve srovnání s vaším kódem, kde máte chybu?
Upravit
Vygenerovaný SQL pro dotaz (viz řádek var sqlString = query.ToString(); ve zdrojovém kódu výše je následující obsah sqlString ) je:
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