使用外键作为一对多中唯一主键的实体框架 [英] Entity Framework using foreign key as only primary key in one to many

问题描述

我首先使用Entity Framework代码设计数据库.

I am using Entity Framework code first to design the database.

我有2个具有一对多关系的模型.一个"Foo"可以具有许多"FooData"，如下所示-

I have 2 models with One to Many relationship. One "Foo" can have many "FooData" as follows -

public class Foo {
  [Key]
  public string serialNumber{get; set;}
  public int someNumber {get; set;}
  public string someName {get; set;}
  // Many more properties
  // Navigation Collection
  public virtual ICollection<FooData> FooDatas{get; set;}
}

public class FooData{
  [Key]
  [ForeignKey("foo")]
  public string SerialNum {get; set;}
  public DateTime SomeTime {get; set;}
  public byte[] SomeData {get; set;}
  // Navigation property
  public virtual Foo foo {get; set;}
}

当我尝试在MVC中使用"Foo"作为脚手架模型为"Foo"添加控制器时，出现了以下错误-角色中的多重性无效.因为从属角色是指键属性，从属角色"多重性的上限必须为1.

When I try to add a controller for "Foo" in MVC, using "Foo" as a scaffolding model, it gives me this error - "Multiplicity is not valid in Role. Because the Dependent Role refers to the key properties, the upper bound of the multiplicity of the Dependent Role must be 1".

在这里，我会有所帮助.

I would appreciate some help here.

谢谢

推荐答案

由于您定义的方式相同，因此两者都使用了相同的键，因此它是一对一的关系.如果您想要一个真实的一对多，则需要添加/创建另一个字段并将其设置为FooData表/实体上的复合键.

Because of how you have it defined the same key is used in both so it is a 1-to-1 relationship. If you want a real one to many you will need to add/create another field and set them up as a composite key on the FooData table/entity.

public class Foo {
    [Key]
    public string serialNumber{get; set;}
    public virtual ICollection<FooData> FooDatas{get; set;}
}

public class FooData {
  [Key, Column(Order = 0),ForeignKey("foo")]
  public string SerialNum {get; set;}
  [Key,Column(Order=1)]
  public int DataId {get;set;}
  public virtual Foo foo {get; set;}
}

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