我在MVC 3應用程序中使用Entity Framework 4.1。我有一個實體，我的主鍵由兩列組成（復合鍵）。這在另一個實體中用作外鍵。如何建立關系？在普通的scnerios中，我們使用：public class Category{ public string CategoryId { get; set; } public string Name { get; set; } public virtual ICollection<Product> Products { get; set; }}public class Product{ public int ProductId { get; set; } public string Name { get; set; } public string CategoryId { get; set; } public virtual Category Category { get; set; }} 但是如果category有兩列鍵怎么辦？
2 回答
慕田峪9158850
TA貢獻1794條經驗 獲得超8個贊
您可以使用任何一種流暢的API：
public class Category
{
public int CategoryId1 { get; set; }
public int CategoryId2 { get; set; }
public string Name { get; set; }
public virtual ICollection<Product> Products { get; set; }
}
public class Product
{
public int ProductId { get; set; }
public string Name { get; set; }
public int CategoryId1 { get; set; }
public int CategoryId2 { get; set; }
public virtual Category Category { get; set; }
}
public class Context : DbContext
{
public DbSet<Category> Categories { get; set; }
public DbSet<Product> Products { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Category>()
.HasKey(c => new {c.CategoryId1, c.CategoryId2});
modelBuilder.Entity<Product>()
.HasRequired(p => p.Category)
.WithMany(c => c.Products)
.HasForeignKey(p => new {p.CategoryId1, p.CategoryId2});
}
}
或數據注釋：
public class Category
{
[Key, Column(Order = 0)]
public int CategoryId2 { get; set; }
[Key, Column(Order = 1)]
public int CategoryId3 { get; set; }
public string Name { get; set; }
public virtual ICollection<Product> Products { get; set; }
}
public class Product
{
[Key]
public int ProductId { get; set; }
public string Name { get; set; }
[ForeignKey("Category"), Column(Order = 0)]
public int CategoryId2 { get; set; }
[ForeignKey("Category"), Column(Order = 1)]
public int CategoryId3 { get; set; }
public virtual Category Category { get; set; }
}
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