Question

如何让实体框架从EsignatureDocument中删除字段和事件（在下面定义）而不会导致错误？我怀疑我可以编写一些模型构建代码，它是在DbContext中的应用程序启动时执行的，使用EntityTypeConfiguration ...构建器代码对于以下示例是什么。

我有一小段C＃可以正常工作。这是：

    var document = _repo.Load<EsignatureDocument>(input.EsignatureDocumentId);

document.Events.Clear();

                document.Fields.Clear();

            _repo.SaveChanges();

当我打电话时，我收到以下错误：

因为一个或多个关系无法改变外键属性是不可为空的。当对a进行更改时关系，相关的外键属性设置为空值。如果外键不支持空值，则为新关系必须定义外键属性必须另外分配必须删除非空值或不相关的对象。

实体框架类如下：

  [Table("EsignatureDocument", Schema = "dbo")]
    public class EsignatureDocument 
    {
        public EsignatureDocument()
        {
            Events = new HashSet<EsignatureDocumentEvent>();
        }
public Guid Id { get; set; }
        public DateTime CreatedDate { get; set; }
        [MaxLength(10)]
        public string DocumentReference { get; set; }
        [MaxLength(100)]
        public string CreatedBy { get; set; }
        [MaxLength(300)]
        public string EnvelopeTitle { get; set; }
        [MaxLength(500)]
        public string Path { get; set; }
        [MaxLength(500)]
        public string SignedPath { get; set; }
        [MaxLength(200)]
        public string SignedUrl { get; set; }
        [MaxLength(200)]
        public string SignableUrl { get; set; }
        public DateTime? SignedDate { get; set; }
        [MaxLength(32)]
        public string EnvelopeFingerprint { get; set; }
        public bool SentByEmail { get; set; }
        public bool SentBySms { get; set; }
        [MaxLength(200)]
        public string EmailAddress { get; set; }
        [MaxLength(20)]
        public string MobileNumber { get; set; }
        [MaxLength(100)]
        public string LetterReference { get; set; }
        public virtual HashSet<EsignatureDocumentEvent> Events { get; set; }
        public virtual HashSet<EsignatureDocumentField> Fields { get; set; }

        [NotMapped]
        public bool IsSigned
        {
            get { return !string.IsNullOrWhiteSpace(SignedPath); }
        }

        [NotMapped]
        public EsignatureDocumentEvent LatestEvent 
        {
            get { return Events.OrderByDescending(x => x.CreatedDate).FirstOrDefault(); } 
        }

    }

[Table("EsignatureDocumentEvent", Schema = "dbo")]
    public class EsignatureDocumentEvent : EntityBase
    {
        public Guid EsignatureDocumentId { get; set; }
        public SignableAction Action { get; set; }
        [MaxLength(50)]
        public string ActionName { get; set; }
        [NotMapped]
        public string ActionDisplayName {
            get
            {
                return char.ToUpper(ActionName[0]) + ActionName.Substring(1).ToLower().Replace("_envelope", string.Empty);
            } 
        }
        public string FieldsJson { get; set; }
        [MaxLength(1000)]
        public string DocumentPdf { get; set; }
        public DateTime CreatedDate { get; set; }
    }

[Table("EsignatureDocumentField", Schema = "dbo")]
    public class EsignatureDocumentField  
    {
        [Key]
        public int Field_Id { get; set; }
        public string Field_Value { get; set; }
        public string Field_Name { get; set; }
        public string Field_Type { get; set; }
        public virtual EsignatureDocument EsignatureDocument { get; set; }
        public Guid EsignatureDocumentId { get; set; }
    }

子表的脚本如下：

CREATE TABLE [dbo].[EsignatureDocumentEvent](
    [Id] [uniqueidentifier] NOT NULL,
    [EsignatureDocumentId] [uniqueidentifier] NOT NULL,
    [Action] [int] NOT NULL,
    [ActionName] [varchar](50) NOT NULL,
    [FieldsJson] [varchar](max) NULL,
    [DocumentPdf] [varchar](1000) NULL,
    [CreatedDate] [datetime] NOT NULL,
 CONSTRAINT [PK_EsignatureDocumentEvent] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO



  ALTER TABLE [dbo].[EsignatureDocumentEvent]  WITH CHECK ADD  CONSTRAINT [FK_EsignatureDocumentEvent_EsignatureDocument] FOREIGN KEY([EsignatureDocumentId])
    REFERENCES [dbo].[EsignatureDocument] ([Id])
    GO

    ALTER TABLE [dbo].[EsignatureDocumentEvent] CHECK CONSTRAINT [FK_EsignatureDocumentEvent_EsignatureDocument]
    GO

CREATE TABLE [dbo].[EsignatureDocumentField](
    [Field_Id] [int] NOT NULL,
    [Field_Name] [varchar](100) NOT NULL,
    [Field_Value] [varchar](1000) NOT NULL,
    [Field_Type] [varchar](100) NOT NULL,
    [EsignatureDocumentId] [uniqueidentifier] NOT NULL,
PRIMARY KEY CLUSTERED 
(
    [Field_Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[EsignatureDocumentField]  WITH CHECK ADD  CONSTRAINT [FK_EsignatureDocumentField_EsignatureDocument] FOREIGN KEY([EsignatureDocumentId])
REFERENCES [dbo].[EsignatureDocument] ([Id])
GO

ALTER TABLE [dbo].[EsignatureDocumentField] CHECK CONSTRAINT [FK_EsignatureDocumentField_EsignatureDocument]
GO

Answer 1

Clear（）删除对父项的引用，而不是子实体本身。

问题是，当您调用document.Fields.Clear（）时，它将使Field实体上的EsignatureDocumentId列无效。由于EsignatureDocumentId不可为空，因此不允许这样做，因此您不能拥有没有父文档的字段。您应该将列标记为可为空，或者您应该使用：

foreach(var f in document.Field) 
{
    Context.DeleteObject(f); //or fieldRepo.Delete(f) or something that fits for 
}

在这种情况下，如何对我的实体执行级联删除？

1 个答案: