I have a table with multiple fields that are foreign keys to a primary key in another table. For example :
Fixture Id (PK)
HomeTeamId (FK to Team.TeamId)
AwayTeamId (FK to Team.TeamId)
HomeTeamCoachId (FK to Coach.CoachId)
AwayTeamCoachId (FK to Coach.CoachId)
Would it be better to separate this data into 2 tables HomeTeam and AwayTeam with a foreign key to FixtureId? This is currently what was generated by Entity Framework :
FixtureId PK
HomeTeamId int
AwayTeamId int
HomeTeamCoachId int
AwayTeamCoachId int
AwayTeam_TeamId FK
HomeTeam_TeamId FK
AwayTeamCoach_CoachId FK
HomeTeamCoach_CoachId FK
This was generated through this class :
public partial class Fixture
{
public int FixtureId { get; set; }
//foreign key
public int AwayTeamId { get; set; }
//navigation properties
public virtual Team AwayTeam { get; set; }
//foreign key
public int HomeTeamId { get; set; }
//navigation properties
public virtual Team HomeTeam { get; set; }
//foreign key
public int AwayCoachId { get; set; }
//navigation properties
public virtual Coach AwayCoach { get; set; }
//foreign key
public int HomeCoachId { get; set; }
//navigation properties
public virtual Coach HomeCoach { get; set; }
}
Can anybody tell me if this is the correct way to do this?
EDIT : In reply to Slauma
So my classes would basically look like this? Or does the configuration in OnModelCreating mean I don't need some of the foreign key related code in my Fixture class?
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// Entity Type Configuration
modelBuilder.Configurations.Add(new TeamConfiguration());
modelBuilder.Configurations.Add(new CoachConfiguration());
modelBuilder.Configurations.Add(new FixtureConfiguration());
modelBuilder.Entity<Fixture>()
.HasRequired(f => f.AwayTeam)
.WithMany()
.HasForeignKey(f => f.AwayTeamId)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Fixture>()
.HasRequired(f => f.HomeTeam)
.WithMany()
.HasForeignKey(f => f.HomeTeamId)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Fixture>()
.HasRequired(f => f.AwayCoach)
.WithMany()
.HasForeignKey(f => f.AwayCoachId)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Fixture>()
.HasRequired(f => f.HomeCoach)
.WithMany()
.HasForeignKey(f => f.HomeCoachId)
.WillCascadeOnDelete(false);
}
public partial class Fixture
{
public int FixtureId { get; set; }
public string Season { get; set; }
public byte Week { get; set; }
//foreign key
public int AwayTeamId { get; set; }
//navigation properties
public virtual Team AwayTeam { get; set; }
//foreign key
public int HomeTeamId { get; set; }
//navigation properties
public virtual Team HomeTeam { get; set; }
//foreign key
public int AwayCoachId { get; set; }
//navigation properties
public virtual Coach AwayCoach { get; set; }
//foreign key
public int HomeCoachId { get; set; }
//navigation properties
public virtual Coach HomeCoach { get; set; }
public byte AwayTeamScore { get; set; }
public byte HomeTeamScore { get; set; }
}
Apparently EF doesn't detect your int
properties like AwayTeamId
as the foreign key for the navigation properties like AwayTeam
because the primary key property in Team
is not Id
but TeamId
. It would probably detect the FKs if they are named like AwayTeamTeamId
or if the primary key property in Team
has the name Id
.
If you don't want to change those property names according to EF convention you can define the FKs with data annotations:
[ForeignKey("AwayTeam")]
public int AwayTeamId { get; set; }
public virtual Team AwayTeam { get; set; }
// the same for the other three FKs
Or Fluent API:
modelBuilder.Entity<Fixture>()
.HasRequired(f => f.AwayTeam)
.WithMany()
.HasForeignKey(f => f.AwayTeamId)
.WillCascadeOnDelete(false);
// the same for the other three FKs
I have disabled cascading delete because it will be enabled by default for a required relationship. But because you have two required relationships to the Team
table (and the Coach
table as well) it would result in two cascading delete paths from Fixture
to Team
and Coach
. Multiple cascading delete paths are forbidden in SQL Server, so you must disable cascading delete for at least one of the two relationships between Fixture
and Team
(and between Fixture
and Coach
).
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