many-to-one ForeignKeys in SQL CE db developed with EF Code First
This is my first foray in either SQL CE or EF, so I may have a lot of misunderstandings. I've searched a lot of blog entries but still can't seem to get this right.
I have an MVC3 web site for registrations for a race we're running. I have a RaceEvents table, and a Runners table, where each RaceEvent will have many runners registered it for it, i.e., Many-to-One. Here are the POCO's with extraneous data stripped out:
public class RaceEvent
{
[Required]
public int Id { get; set; }
public virtual ICollection<Runner> Runners { get; set; }
}
public class Runner
{
[Required]
public int Id { get; set; }
[Required]
public int RaceEventId { get; set;}
[ForeignKey("RaceEventId")]
public RaceEvent RaceEvent { get; set; }
}
Which, as much as I can figure out, ought to work. As I understand it, it should figure out by convention that RaceEventId is a foreign key to RaceE开发者_运维百科vents. And if that's not good enough, I'm telling it with the ForeignKey attribute.
However, it doesn't seem to be working. Whenever I insert a new runner, it is also inserting a new entry in the RaceEvents table. And when I look at the table diagram in ServerExplorer, it shows two gold keys at the top of the Runners table diagram, one for Id, identified in the properties as a PrimaryKey, and the other for RaceEventId, not identified as a PrimaryKey, but indicated in the properties to be for table Runners, rather than for table RaceEvents. I would expect a gold key for Id, but a silver ForeignKey for RaceEventId.
FWIW, I don't really care about the ICollection in the RaceEvent, but the blog entries all seemed to imply that it was necessary.
Can anybody help me get this right?
Thanks.
Ok,
Sorry I did not read your question in enough detail. In our project this is how we would represent what your doing. I looked in SSMS and it is not showing said grey key, but it does not create a race event every time you add a runner. Although you do need to make sure when you create a runner that you set the race event property.
public class DB : DbContext
{
public DB()
: base("Data Source=(local);Initial Catalog=DB;Integrated Security=True")
{
}
public IDbSet<Runner> Runners { get; set; }
public IDbSet<RaceEvent> RaceEvents { get; set; }
}
public class RaceEvent
{
[Key]
public int RaceEventID { get; set; }
}
public class Runner
{
[Key]
public int RunnerID { get; set; }
[Required]
public virtual RaceEvent RaceEvent { get; set; }
}
Any question let me know.
You need to override the model creating in the DbContext. Below is a sample for AnsNet_User & AspNet_Roles N:N relationship
protected override void OnModelCreating(DbModelBuilder dbModelBuilder)
{
dbModelBuilder.Entity<aspnet_Users>().HasMany(a => a.aspnet_Roles).WithMany(b =>
b.aspnet_Users).Map(
m =>
{
m.MapLeftKey("UserId");
m.MapRightKey("RoleId");
m.ToTable("aspnet_UsersInRoles");
});
base.OnModelCreating(dbModelBuilder);
}
精彩评论