asp.net - INSERT语句与FOREIGN KEY约束冲突

Question

我是一个绿色的asp.net开发人员，并且在我的项目中使用了最新的 Entity Framework 。我在使用自动生成的值播种数据库时遇到问题(我认为)。这是确切的错误。



这是代码:

public class Address
{
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int AddressId { get; set; }
// some more properties
}

public class ApplicationUser : IdentityUser
{
        [ForeignKey("Address")]        
    public int AddressId { get; set; }
    public Address Address { get; set; }

// some more properties
}

public class Shelter
{
        [Required]
        [ForeignKey("Address")]
        public int AddressId { get; set; }
        public Address Address { get; set; }
// some more properties
}
//seed
private void CreateShelters()
{
    EntityEntry<Address> MspcaAddress = DbContext.Addresses.Add(new Address()
    {
                Street = "350 S Huntington Ave",
                City = "Jamaica Plain",
                State = "MA",
                AreaCode = "02130",
                Latitude = 42.3228928,
                Longititude = -71.11120540000002
    });
     EntityEntry<Address> BostonAnimalCareAndControlAddress = DbContext.Addresses.Add(new Address()
     {
                Street = "26 Mahler Rd",
                City = "Roslindale",
                State = "MA",
                AreaCode = "02131",
                Latitude = 42.2943377,
                Longititude = -71.12153390000003
            });
            EntityEntry<Address> AnimalRescueLeagueOfBostonAddress = DbContext.Addresses.Add(new Address()
            {
                Street = "10 Chandler St",
                City = "Boston",
                State = "MA",
                AreaCode = "0S2116",
                Latitude = 42.3470486,
                Longititude = -71.06976929999996
            });

            EntityEntry<Shelter> Mspca = DbContext.Shelters.Add(new Shelter()
            {
                Name = "MCSPA",
                AddressId = MspcaAddress.Entity.AddressId
            });
            EntityEntry<Shelter> BostonAnimalCareAndControl = DbContext.Shelters.Add(new Shelter()
            {
                Name = "Boston Animal Care And Control",
                AddressId = BostonAnimalCareAndControlAddress.Entity.AddressId
            });
            EntityEntry<Shelter> AnimalRescueLeagueOfBoston = DbContext.Shelters.Add(new Shelter()
            {
                Name = "Animal Rescue League Of Boston Address",
                AddressId = AnimalRescueLeagueOfBostonAddress.Entity.AddressId
            });
            DbContext.SaveChanges();
   }

我尝试重新创建数据库，以查看是否存在数据/表不一致的问题，但仍然出现错误。有任何想法吗？

Answer 1

您尝试播种的“Shelter”实体要求您提交现有的AddressID上面的代码尝试获取尚未创建的地址的AddressId。

您必须首先将地址提交到数据库(使用DbContext.SaveChanges();)

然后，您可以使用检索到的AddressId创建Shelter实体。下面的代码显示了如何执行此操作的示例，但是您可能必须重新编写获取addressId的查询。或者，您可能必须将它们与插入过程完全分开。

    private void CreateShelters()
{
    EntityEntry<Address> MspcaAddress = DbContext.Addresses.Add(new Address()
    {
                Street = "350 S Huntington Ave",
                City = "Jamaica Plain",
                State = "MA",
                AreaCode = "02130",
                Latitude = 42.3228928,
                Longititude = -71.11120540000002
    });
     EntityEntry<Address> BostonAnimalCareAndControlAddress = DbContext.Addresses.Add(new Address()
     {
                Street = "26 Mahler Rd",
                City = "Roslindale",
                State = "MA",
                AreaCode = "02131",
                Latitude = 42.2943377,
                Longititude = -71.12153390000003
            });
            EntityEntry<Address> AnimalRescueLeagueOfBostonAddress = DbContext.Addresses.Add(new Address()
            {
                Street = "10 Chandler St",
                City = "Boston",
                State = "MA",
                AreaCode = "0S2116",
                Latitude = 42.3470486,
                Longititude = -71.06976929999996
            });

    DbContext.SaveChanges();


            EntityEntry<Shelter> Mspca = DbContext.Shelters.Add(new Shelter()
            {
                Name = "MCSPA",
                AddressId = MspcaAddress.Entity.AddressId
            });
            EntityEntry<Shelter> BostonAnimalCareAndControl = DbContext.Shelters.Add(new Shelter()
            {
                Name = "Boston Animal Care And Control",
                AddressId = DbContext.Addresses.Where(x => x.Street == "26 Mahler Rd").FirstOrDefault().AddressId
       });
            EntityEntry<Shelter> AnimalRescueLeagueOfBoston = DbContext.Shelters.Add(new Shelter()
            {
                Name = "Animal Rescue League Of Boston Address",
                AddressId = DbContext.Addresses.Where(x => x.Street == "10 Chandler St").FirstOrDefault().AddressId

            });
            DbContext.SaveChanges();
   }

希望这足以让您接受。如果对addressId的查询不起作用，请告诉我，我们将很乐意为您提供帮助。