Entity Framework Code First One-To-Many doing wrong queries? - entity-framework

Question

So I have a model
public class Player
{
public int PlayerId { get; set; }
[Required]
public string Name2 { get; set; }
public string Cv { get; set; }
public int TeamId { get; set; }
public virtual Team Team { get; set; }
}
public class Team
{
public int TeamId { get; set; }
[Required]
public string Name { get; set; }
public string City { get; set; }
public DateTime Founded { get; set; }
public virtual IList<Player> Players { get; set; }
}
My Teams table in DB contains records, my Players table in DB does not contain any (empty).
When I run this query:
IQueryable<Player> query = playerRepository.All.Include(p => p.Team);
return View((query);
I get this query in DB (via profiler):
SELECT
[Project1].[TeamId] AS [TeamId],
[Project1].[Name] AS [Name],
[Project1].[City] AS [City],
[Project1].[Founded] AS [Founded],
[Project1].[C1] AS [C1],
[Project1].[PlayerId] AS [PlayerId],
[Project1].[Name2] AS [Name2],
[Project1].[Cv] AS [Cv],
[Project1].[TeamId1] AS [TeamId1]
FROM ( SELECT
[Limit1].[TeamId] AS [TeamId],
[Limit1].[Name] AS [Name],
[Limit1].[City] AS [City],
[Limit1].[Founded] AS [Founded],
[Extent2].[PlayerId] AS [PlayerId],
[Extent2].[Name2] AS [Name2],
[Extent2].[Cv] AS [Cv],
[Extent2].[TeamId] AS [TeamId1],
CASE WHEN ([Extent2].[PlayerId] IS NULL) THEN CAST(NULL AS int)
ELSE 1
END AS [C1]
FROM ( SELECT TOP (10) [c].[TeamId] AS [TeamId],
[c].[Name] AS [Name],
[c].[City] AS [City],
[c].[Founded] AS [Founded]
/* HERE */
FROM [dbo].[Teams] AS [c]
) AS [Limit1]
/* AND HERE */
LEFT OUTER JOIN [dbo].[Players] AS [Extent2]
ON [Limit1].[TeamId] = [Extent2].[TeamId]
) AS [Project1]
ORDER BY [Project1].[TeamId] ASC, [Project1].[C1] ASC
Which as a result I get one empty row shown on the screen. This is because this joins are done in wrong order...instead of joining Teams on Players, I get Players on Teams...which in turn means that even though I have NO players in the DB, I get an empty row in the grid.
Anyone have any ideas why???
Vladan

Answer 1

You must be doing something wrong or you are looking at wrong query. I used your entities and your linq query:
var data = context.Players.Include(p => p.Team).ToList();
and I get this SQL query:
SELECT
[Extent1].[PlayerId] AS [PlayerId],
[Extent1].[Name2] AS [Name2],
[Extent1].[Cv] AS [Cv],
[Extent1].[TeamId] AS [TeamId],
[Extent2].[TeamId] AS [TeamId1],
[Extent2].[Name] AS [Name],
[Extent2].[City] AS [City],
[Extent2].[Founded] AS [Founded]
FROM [dbo].[Players] AS [Extent1]
INNER JOIN [dbo].[Teams] AS [Extent2] ON [Extent1].[TeamId] = [Extent2].[TeamId]
But if I use this query:
var data = context.Teams.Include(t => t.Players).Take(10).ToList();
I will get exactly your SQL query. TOP (10) and reverse table querying will not appear without reason.