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[英]Cannot insert explicit value for identity column when IDENTITY_INSERT is set to OFF. (Entity Framework Core)
[英]Entity framework core: Cannot insert explicit value for identity column in table 'Relation' when IDENTITY_INSERT is set to OFF
我正在建立一個應用程序,當我想將表單插入到表單表中時,出現以下錯誤:
當IDENTITY_INSERT設置為OFF時,無法為表'Relation'中的Identity列插入顯式值。
這些是我的模型:
表格模型:
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[ForeignKey("FormType")]
public int? TypeId { get; set; }
public virtual FormType Type { get; set; }
[ForeignKey("FormStatusType")]
public int? StatusTypeId { get; set; }
public virtual FormStatusType StatusTknype { get; set; }
[ForeignKey("Relation")]
public int? SupplierId { get; set; }
public virtual Relation Supplier { get; set; }
[ForeignKey("Relation")]
public int? CustomerId { get; set; }
public virtual Relation Customer { get; set; }
public String SupplierReference { get; set; }
public Guid ApiId { get; set; }
public DateTime DueDate { get; set; }
public FormFile FormFiles { get; set; }
public String FormName { get; set; }
public DateTime UploadDate { get; set; }
關系模型:
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[ForeignKey("FormType")]
public int? TypeId { get; set; }
public virtual FormType Type { get; set; }
[ForeignKey("FormStatusType")]
public int? StatusTypeId { get; set; }
public virtual FormStatusType StatusTknype { get; set; }
[ForeignKey("Relation")]
public int? SupplierId { get; set; }
public virtual Relation Supplier { get; set; }
[ForeignKey("Relation")]
public int? CustomerId { get; set; }
public virtual Relation Customer { get; set; }
public String SupplierReference { get; set; }
public Guid ApiId { get; set; }
public DateTime DueDate { get; set; }
public FormFile FormFiles { get; set; }
public String FormName { get; set; }
public DateTime UploadDate { get; set; }
我的上下文如下所示:
public class DataContext: DbContext
{
public DataContext(DbContextOptions<DataContext> options): base(options)
{
}
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
base.OnConfiguring(optionsBuilder);
optionsBuilder.UseSqlServer();
}
public DbSet<Relation> Relation { get; set; }
public DbSet<Setting> Settings { get; set; }
public DbSet<Notification> Notification { get; set; }
public DbSet<FormStatusType> FormStatusType { get; set; }
public DbSet<File> File { get; set; }
public DbSet<FormFile> FormFile { get; set; }
public DbSet<FormType> FormType { get; set; }
public DbSet<Form> Form { get; set; }
public DbSet<User> User { get; set; }
public DbSet<RelationUser> RelationUser { get; set; }
public DbSet<SupplierCustomer> SupplierCustomer { get; set; }
}
我用來添加表單的方法如下所示:
public async Task<Form> AddForm(Form form, int currentUserId)
{
try
{
if (form != null)
{
//huidige gebruiker als supplier aanduiden
Relation r = await GetCurrentUser(currentUserId);
form.Supplier = r;
form.SupplierId = r.Id;
//form aan de db toevoegen
_datacontext.Form.Add(form);
_datacontext.SaveChanges();
return form;
}
else
{
return null;
}
}
catch (Exception e)
{
LogError(e);
return null;
}
}
獲取當前用戶方法
private async Task<Relation> GetCurrentUser(int currentUserId)
{
var relation = from r in _datacontext.RelationUser
where r.UserId == currentUserId
select r.Relation;
return await relation.FirstOrDefaultAsync();
}
這是我調用AddForm方法的地方:
[HttpPost]
[Route("addform")]
[Authorize]
// api/form/addform
public async Task<IActionResult> AddForm([FromBody] Form form)
{
if (ModelState.IsValid)
{
Form f = await _formRepository.AddForm(form, GetUserIdFromToken());
if(f != null)
{
QueueObject qo = new QueueObject()
{
ActionTypeId = 1,
FormId = f.Id
};
await new QueueHandler().SendMessageToQueue(qo);
}
return Ok(f);
}
else
{
return NotFound("model is niet geldig");
}
}
我已經搜索過,但沒有找到解決問題的方法
您的模型有多個錯誤。 ForeignKey屬性必須指向類中的屬性,而不是依賴實體的類型:
//FORM MODEL
[ForeignKey("Type")]
public int? TypeId { get; set; }
public virtual FormType Type { get; set; }
[ForeignKey("StatusTknype")]
public int? StatusTypeId { get; set; }
public virtual FormStatusType StatusTknype { get; set; }
[ForeignKey("Supplier")]
public int? SupplierId { get; set; }
public virtual Relation Supplier { get; set; }
[ForeignKey("Customer")]
public int? CustomerId { get; set; }
public virtual Relation Customer { get; set; }
//RELATION MODEL
[ForeignKey("Type")]
public int? TypeId { get; set; }
public virtual FormType Type { get; set; }
[ForeignKey("StatusTknype")]
public int? StatusTypeId { get; set; }
public virtual FormStatusType StatusTknype { get; set; }
[ForeignKey("Relation")]
public int? SupplierId { get; set; }
public virtual Relation Supplier { get; set; }
[ForeignKey("Customer")]
public int? CustomerId { get; set; }
public virtual Relation Customer { get; set; }
另外,如果遵循Convention over Configuration ,則可以僅按常規方式命名屬性來完全刪除ForeignKeyAttribute:
public int? StatusTypeId { get; set; }
public virtual FormStatusType StatusType { get; set; }
發生這種情況的另一個可能原因是,如果您在嘗試向數據庫中插入新實體時對SaveChanges
某些調用超時,然后嘗試使用相同的DbContext
實例再次調用SaveChanges
。
這是可重現的:
using(var context = new MyDbContext())
{
context.People.Add(new Person("John"));
try
{
// using SSMS, manually start a transaction in your db to force a timeout
context.SaveChanges();
}
catch(Exception)
{
// catch the time out exception
}
// stop the transaction in SSMS
context.People.Add(new Person("Mike"));
context.SaveChanges(); // this would cause the exception
}
當IDENTITY_INSERT設置為OFF時,最后一次SaveChanges
將導致無法在表'People'中為標識列插入顯式值 。
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