EF代码第一个单向导航属性

Question

I have the following entities:

[KnownType(typeof(Script))]
public class Application : IEntity
{
    public long ID { get; set; }
    public string Name { get; set; }
    public long? StartScriptID { get; set; }
    // Other properties...

    // Navigation properties:
    public virtual Script StartScript { get; set; }   // new
    public virtual List<Script> Scripts { get; set; }
}

[KnownType(typeof(Application))]
public class Script : IEntity
{
    public long ID { get; set; }
    public string Name { get; set; }
    // Other properties...

    // Navigation properties:
    public virtual Application Application { get; set; }
}

I have no fluent configurations on the DbContext

So the model exists of Scripts which must be bound to an application. Applications can have a startScript defined. All this I already have working.

Now I am in need of a navigation property: Application.StartScript .

The question is how can I add the navigation property on Application without having to add a the equivalent navigation property on Script .

Thanks in advance!

---

EDIT: When I run Add-Migration the following migration code is generated:

public override void Up()
{
    DropForeignKey("dbo.Scripts", "ApplicationID", "dbo.Applications");
    AddColumn("dbo.Scripts", "Application_ID", c => c.Long());
    CreateIndex("dbo.Applications", "StartScriptID");
    CreateIndex("dbo.Scripts", "Application_ID");
    AddForeignKey("dbo.Applications", "StartScriptID", "dbo.Scripts", "ID");
    AddForeignKey("dbo.Scripts", "Application_ID", "dbo.Applications", "ID");
}

This creates a new column on Scripts which I don't need, as I already have the StartScriptID column.

EDIT: Update after @haim770 answer

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Application>().HasOptional(x => x.StartScript).WithOptionalDependent(x => x.Application);
}

public override void Up()
{
    DropForeignKey("dbo.Scripts", "ApplicationID", "dbo.Applications");
    DropIndex("dbo.Scripts", new[] { "ApplicationID" });
    RenameColumn(table: "dbo.Applications", name: "ApplicationID", newName: "StartScript_ID");
    AddColumn("dbo.Scripts", "Application_ID", c => c.Long());
    CreateIndex("dbo.Applications", "StartScript_ID");
    CreateIndex("dbo.Scripts", "Application_ID");
    AddForeignKey("dbo.Scripts", "Application_ID", "dbo.Applications", "ID");
    AddForeignKey("dbo.Applications", "StartScript_ID", "dbo.Scripts", "ID");
}

It doesn't understand that it should use the already existing StartScriptID. Is there a way to point it in the right direction?

EDIT: Wanted database structure:

Applications:

• ID, PK, bigint, not null
• Name, nvarchar(max), not null
• StartScriptID, bigint, null

Scripts:

• ID, PK, bigint, not null
• Name, nvarchar(max), not null
• ApplicationID, FK, bigint, not null

EDIT:

public class Application
{
    [InverseProperty("StartScript")]
    public long? StartScriptID { get; set; }
    [ForeignKey("StartScriptID")]
    public virtual Script StartScript { get; set; }
}

I was thinking there was no changes needed in the database, so I have tried adding migration with -IgnoreChanges. But then I got an EntityCommandExecutionException when querying for entities: "Invalid column name 'Application_ID'". So the Entity Framework needs some configuration for telling to use the StartScriptID property.

Answer 1

You can modify the mapping using the ForeignKeyAttribute and the InversePropertyAttribute . If that doesn't work the way you want, you can always edit the migration yourself before applying it.

If you want to customize the column name, try the ColumnAttribute:

public class Application
{
    [Column("DatabaseColumnName")]
    public long? StartScriptID { get; set; }
    [ForeignKey("StartScriptID")]
    public virtual Script StartScript { get; set; }
}

A longer explanation can be found here: http://msdn.microsoft.com/de-de/data/gg193958.aspx

Answer 2

Try to use EntityTypeConfiguration It makes more easy to handle this kind of problem. Then:

public class Application 
{
    public long ID { get; set; }
    public string Name { get; set; }
    public long? StartScriptID { get; set; }
    // Other properties...

    // Navigation properties:
    public virtual Script StartScript { get; set; }   // new
    public virtual ICollection<Script> Scripts { get; set; }
}

public class Script 
{
    public long ID { get; set; }
    public string Name { get; set; }
    public int ApplicationId { get; set; }
    // Other properties...

    // Navigation properties:
    public virtual Application Application { get; set; }
}

public class ApplicationMap : EntityTypeConfiguration<Application>
{
    public ApplicationMap()
    {
        this.HasKey(t => t.ID);

        this.ToTable("TB_APLICATION", "aplication");

        this.Property(t => t.ID).HasColumnName("id");
        this.Property(t => t.Name).HasColumnName("name");
        this.Property(t => t.StartScriptID).HasColumnName("startscript_id");

        this.HasOptional(t => t.StartScript)
            .WithMany()
            .HasForeignKey(t => t.StartScriptID);
    }
}

public class ScriptMap : EntityTypeConfiguration<Script>
{
    public ScriptMap()
    {
        this.HasKey(t => t.ID);

        this.ToTable("TB_APLICATION", "aplication");

        this.Property(t => t.ID).HasColumnName("id");
        this.Property(t => t.Name).HasColumnName("name");

        this.HasRequired(t => t.Application)
            .WithMany(w => w.Scripts)
            .HasForeignKey(t => t.ApplicationId);
    }
}

Don't forget to tell EF about the Mappings: (Call it inside OnModelCreating )

public static class MappingConfig
{
     public static void ConfigureMap(DbModelBuilder modelBuilder)
     {
         modelBuilder.Configurations.Add(new ApplicationMap());
         modelBuilder.Configurations.Add(new ScriptMap());
     }
 }