[英]EF Core - Unable to determine the relationship represented by navigation (One-to-Many)
我正在嘗試創建一個簡單的一對多關系,但 Ef Core 不知何故無法識別它。 我仍然是這方面的初學者,但我認為我是按書本做的(完全定義了關系),所以我不明白為什么 EF Core 會拋出這個錯誤:
無法確定“保險”類型的導航“資產.保險”表示的關系。 手動配置關系,或使用“[NotMapped]”屬性或使用“OnModelCreating”中的“EntityTypeBuilder.Ignore”忽略此屬性。
這是我的兩個模型: Asset.cs
public class Asset
{
public int AssetId { get; set; }
public string AssetName { get; set; }
[ForeignKey("AssetTypeId")]
public int AssetTypeId { get; set; }
public AssetType AssetType { get; set; }
public ICollection<AssetValue> AssetTypeValues { get; set; }
public string Brand { get; set; }
public string Model { get; set; }
public string SerialNumber { get; set; }
public string ProductNumber { get; set; }
public DateTime PurchaseDate { get; set; }
public decimal PurchasePrice { get; set; }
[ForeignKey("LocationId")]
public int? LocationId { get; set; }
public Location Location { get; set; }
[ForeignKey("InsuranceId")]
public int InsuranceId { get; set; }
public Insurance Insurance { get; set; }
[ForeignKey("OwnerId")]
public string? OwnerId { get; set; }
public AppUser Owner { get; set; }
[ForeignKey("InvoiceId")]
public int? InvoiceId { get; set; }
public Insurance Invoice { get; set; }
public string? ImagePath { get; set; }
public string? Description { get; set; }
public string CreatedBy { get; set; }
public string ModifiedBy { get; set; }
public DateTime DateCreated { get; set; }
public DateTime DateModified { get; set; }
}
保險.cs
public class Insurance
{
public int InsuranceId { get; set; }
[ForeignKey("InsuranceTypeId")]
public int InsuranceTypeId { get; set; }
public InsuranceType InsuranceType { get; set; }
public string Insurer { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public string? FilePath { get; set; }
public string? Description { get; set; }
public string CreatedBy { get; set; }
public string ModifiedBy { get; set; }
public DateTime DateCreated { get; set; }
public DateTime DateModified { get; set; }
public ICollection<Asset> Assets { get; set; }
}
此外,如果我刪除這種關系,只是為了測試,遷移仍然不起作用,並且會拋出有關資產 model 中其他外鍵的錯誤。 是不是因為我有太多外鍵所以我必須在 OnModelCreating 中定義它們?
編輯:ApplicationDbContext
public class ApplicationDbContext : IdentityDbContext<AppUser>
{
public DbSet<Asset> Assets { get; set; }
public DbSet<AssetType> AssetTypes { get; set; }
public DbSet<AssetProp> AssetProps { get; set; }
public DbSet<AssetValue> AssetValues { get; set; }
public DbSet<Location> Locations { get; set; }
public DbSet<Company> Companies { get; set; }
public DbSet<CompanyContact> CompanyContacts { get; set; }
public DbSet<Invoice> Invoices { get; set; }
public DbSet<InsuranceType> InsuranceTypes { get; set; }
public DbSet<Insurance> Insurances { get; set; }
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
}
如果您指定[ForeignKey]
屬性,則需要執行以下兩項操作之一:
所以要么:
[ForeignKey("Insurance")]
public int InsuranceId { get; set; }
public Insurance Insurance { get; set; }
或者:
public int InsuranceId { get; set; }
[ForeignKey("InsuranceId")]
public Insurance Insurance { get; set; }
通過將屬性放在標量屬性上並指定標量屬性的名稱,EF 無法理解您要做什么。
這適用於代碼中的所有[ForeignKey("...")]
屬性。
注意:由於每個給定實體類型只有一個導航屬性,並且標量屬性名稱與添加了Id
后綴的導航屬性名稱相匹配,因此實際上不需要[ForeignKey]
屬性。
Insurance
實體有兩個導航屬性:
public Insurance Insurance { get; set; }
...
public Insurance Invoice { get; set; }
我懷疑第二個應該是:
public Invoice Invoice { get; set; }
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