Question

我有ApplicationForm类来存储申请该网站的用户信息。 ApplicationFormAnswer用于在每个申请表中存储自定义字段答案。

 public class ApplicationFormAnswer
    {
        public Guid Id { get; set; }
        public string FieldId { get; set; }
        public ApplicationCustomFieldType FieldType { get; set; }
        public string Name { get; set; }
        public string Answer { get; set; }
        public virtual ApplicationForm ApplicationForm { get; set; }
        public Guid ApplicationFormId { get; set; }
    }

和在ApplicationForm类中

public class ApplicationForm
{
    public Guid Id { get; set; }
    .....
    ....
    public virtual ICollection<ApplicationFormAnswer> ApplicationFormAnswers { get; set; }
}

当我尝试进行迁移时，它给了我这个错误：

在引用表'dbo.ApplicationForms'中没有与外键'FK_dbo.ApplicationFormAnswers_dbo.ApplicationForms_ApplicationFormId'中的引用列列表匹配的主键或候选键。无法创建约束或索引。查看以前的错误。

编辑：

当我应用-verbose时，我看到创建了SQL查询：

CREATE TABLE [dbo].[ApplicationFormAnswers] (
    [ApplicationFormId] [uniqueidentifier] NOT NULL,
    [Id] [uniqueidentifier] NOT NULL,
    [FieldId] [nvarchar](max),
    [FieldType] [int] NOT NULL,
    [Name] [nvarchar](max),
    [Answer] [nvarchar](max),
    [ApplicationFormCustomField_FieldId] [nvarchar](max),
    [ApplicationFormCustomField_Order] [int] NOT NULL,
    [ApplicationFormCustomField_Name] [nvarchar](max),
    [ApplicationFormCustomField_FieldType] [int] NOT NULL,
    [ApplicationFormCustomField_IsRequired] [bit] NOT NULL,
    [ApplicationFormCustomField_IsIncluded] [bit] NOT NULL,
    [ApplicationFormCustomField_CanBeDeleted] [bit] NOT NULL,
    [ApplicationFormCustomField_IsDeleted] [bit] NOT NULL,
    CONSTRAINT [PK_dbo.ApplicationFormAnswers] PRIMARY KEY ([ApplicationFormId])
)
CREATE INDEX [IX_Id] ON [dbo].[ApplicationFormAnswers]([Id])
ALTER TABLE [dbo].[ApplicationFormAnswers] ADD CONSTRAINT [FK_dbo.ApplicationFormAnswers_dbo.ApplicationForms_Id] FOREIGN KEY ([Id]) REFERENCES [dbo].[ApplicationForms] ([Id]) ON DELETE CASCADE

我看到它使ApplicationFormId成为主键，但主键应为ID。我试图将[Key]放在ID上方，但仍然无法正常工作。

Answer 1

我认为问题在于，您将[ApplicationFormId]设置为唯一标识符时，只是一个FK。

只需将int中的ApplicationFormAnswers输入[ApplicationFormId]

Answer 2

由于您的Id属性是GUID而不是int，因此EF不会自动将其识别为ID。您可以使用[KeyAttribute]或流利的API手动配置ID：

public class ApplicationFormAnswer
{
     [Key]
     public Guid Id { get; set; }
     //...
}

public class ApplicationForm
{
     [Key]
     public Guid Id { get; set; }
     //...
}

...或...

modelBuilder.Entity<ApplicationFormAnswer>().HasKey(e => e.Id);

您还应该手动配置外键：

public class ApplicationFormAnswer
{
     [Key]
     public Guid Id { get; set; }
     public Guid ApplicationFormId { get; set; }
     [ForeignKey("ApplicationFormId")]         
     public virtual ApplicationForm ApplicationForm { get; set; }
     //...
}

...或...

modelBuilder.Entity<ApplicationFormAnswer>()
    .HasOne(e => e.ApplicationForm)
    .WithMany(e => e.ApplicationFormAnswers)
    .HasForeignKey(e => e.ApplicationFormId);

EntityFramework-引用的表中没有主键或候选键

2 个答案: