Entity Framework中多个列的唯一键限制 [英] Unique Key constraints for multiple columns in Entity Framework

问题描述

  public class Entity 
 {
 [ Key，DatabaseGenerated（DatabaseGeneratedOption.Identity）] 
 public string EntityId {get; set;} 
 public int FirstColumn {get; set;} 
 public int SecondColumn {get; set;} 
} 
  

我想使 FirstColumn 和 SecondColumn 作为唯一的。

示例：

  Id FirstColumn SecondColumn 
 1 1 1 = OK 
 2 2 1 = OK 
 3 3 3 = OK 
 5 3 1 =这个OK 
 4 3 3 = GRRRRR！这里错误
  

有没有办法？

解决方案

使用实体框架6.1，您现在可以执行此操作：

  [Index（IX_FirstAndSecond，1，IsUnique = true）] 
 public int FirstColumn {get;组; } 
 
 [Index（IX_FirstAndSecond，2，IsUnique = true）] 
 public int SecondColumn {get;组; } 
  

属性中的第二个参数是可以在索引中指定列的顺序。

更多信息： MSDN

I'm using Entity Framework 5.0 Code First;

public class Entity
 {
   [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
   public string EntityId { get; set;}
   public int FirstColumn  { get; set;}
   public int SecondColumn  { get; set;}
 }

I want to make the combination between FirstColumn and SecondColumn as unique.

Example:

Id  FirstColumn  SecondColumn 
1       1              1       = OK
2       2              1       = OK
3       3              3       = OK
5       3              1       = THIS OK 
4       3              3       = GRRRRR! HERE ERROR

Is there anyway to do that?

解决方案

With Entity Framework 6.1, you can now do this:

[Index("IX_FirstAndSecond", 1, IsUnique = true)]
public int FirstColumn { get; set; }

[Index("IX_FirstAndSecond", 2, IsUnique = true)]
public int SecondColumn { get; set; }

The second parameter in the attribute is where you can specify the order of the columns in the index.
More information: MSDN

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