Code First Migration想要爲不同的DbContext中的一個實體創建表格

Question

假設我有3個實體：A，B和C;

public class A // Target entity 
{ 
    public int Foo { get; set; } 
    public int Bar { get; set; } 
} 

public class B 
{ 
    public virtual ICollection<C> C { get; set; } // Navigation to C 
} 

public class C 
{ 
    public virtual A A { get; set; } // Navigation to A 
} 

...和目前單一上下文：X

public abstract class Context : DbContext 
{ 
    protected const string CONNECTION_NAME = "some_connection_name"; 
    protected const string SCHEMA_NAME = "dbo"; 

    public Context() : base(CONNECTION_NAME) 
    { 
     Database.Log = message => Debug.WriteLine(message); 
    } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     modelBuilder.HasDefaultSchema(SCHEMA_NAME); 
     modelBuilder.Conventions.Remove<PluralizingTableNameConvention>(); 
     modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>(); 
     modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>(); 
    } 
} 

public class X : Context 
{ 
    public DbSet<A> A { get; set; } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     modelBuilder.Configurations.Add(new AConfiguration()); 
     base.OnModelCreating(modelBuilder); 
    } 
} 

的問題是，我通過導航屬性添加第二上下文（Y），因此該實體Ç指向一個，Code First Migrations想要爲實體A創建一個表，但它已經存在。

public class Y : Context 
{ 
    public DbSet<B> B { get; set; } 

    public DbSet<C> C { get; set; } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     modelBuilder.Configurations.Add(new BConfiguration()); 
     modelBuilder.Configurations.Add(new CConfiguration()); 
     base.OnModelCreating(modelBuilder); 
    } 
} 

我該如何克服這個問題？

Answer 1

第二方面應該明確Ignore的A實體：

public class Y : Context 
{ 
    public DbSet<B> B { get; set; } 

    public DbSet<C> C { get; set; } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     modelBuilder.Configurations.Add(new BConfiguration()); 
     modelBuilder.Configurations.Add(new CConfiguration()); 

     modelBuilder.Ignore<A>(); 

     base.OnModelCreating(modelBuilder); 
    } 
}