1

已使用 EF Core 在 SQLite 数据库中插入订单。尝试向该订单添加订单详细信息，如下所示，SaveChanges引发异常

SQLite 错误 19：“外键约束失败”

代码：

using (DataContext dbase = new())
{
    string orderId = "ef5011f6-8fa0-4483-a9bd-2a2b7de73ba6";

    Order order = dbase.Orders.Include(o => o.OrderDetails).Single(o => o.OrderId == orderId);

    v11OrderDetail.ItemDescription = v10OrderDetail.ItemDescription;
    v11OrderDetail.NrUnits = v10OrderDetail.NrUnits;
    v11OrderDetail.OrderDetailId = v10OrderDetail.OrderDetailId;
    v11OrderDetail.UnitCost = v10OrderDetail.UnitCost;
    v11OrderDetail.UnitPrice = v10OrderDetail.UnitPrice;
    v11OrderDetail.Order = order;
    v11OrderDetail.OrderId = order.OrderId;

    order.OrderDetails.Add(v11OrderDetail);

    dbase.SaveChanges();
}

在调用之前，SaveChanges我可以看到它order是从数据库中正确填充的，v11OrderDetail.Order是保存的订单，v11OrderDetail.OrderId也是正确的。

这个OrderDetail类看起来像这样

public class OrderDetail
{
    private string _OrderDetailId = Guid.NewGuid().ToString();

    public string OrderDetailId
    {
        get { return _OrderDetailId; }
        set { _OrderDetailId = value; }
    }

    private string _OrderId;
    public string OrderId
    {
        get { return Order.OrderId; }
        set { _OrderId = Order.OrderId; }
    }

    public virtual Order Order { get; set; }

    private string? _JobId;
    public string? JobId
    {
        get { return Job?.JobId; }
        set { _JobId = Job?.JobId; }
    }

    public virtual Job? Job { get; set; } // may be null for item sales

    private string _ItemCode;
    public string ItemCode
    {
        get { return _ItemCode; }
        set
        {
            if (value.Length > Defaults.StockCodeLength)
                value = value.Substring(0, Defaults.StockCodeLength);
            _ItemCode = value;
        }
    }

    private string _ItemDescription = Defaults.Description;
    public string ItemDescription
    {
        get { return _ItemDescription; }
        set
        {
            if (value.Equals(_ItemDescription))
                return;
            if (value.Length > Defaults.DescriptionLength)
                value = value.Substring(0, Defaults.DescriptionLength);
            _ItemDescription = value;
        }
    }
  
    public decimal UnitCost { get; set; }

    private int _NrUnits = 1;
    public int NrUnits
    {
        get { return _NrUnits; }
        set
        {
            if (value < 1)
                throw new ArgumentException($"{nameof(NrUnits)} cannot be < 1");
            _NrUnits = value;
        }
    }

    public decimal UnitPrice { get; set; }
    public decimal Net => Total / (1 + Order.TaxRate / 100);
    public decimal Tax => Total - Net;
    public decimal Total => NrUnits * UnitPrice;

    public OrderDetail(string itemCode)
    {
        this._ItemCode = itemCode;
    }
}

OrderDetail集合在类Order中声明

public virtual ICollection<OrderDetail> OrderDetails { get; private set; } = new ObservableCollection<OrderDetail>();

在里面DataContext

public DbSet<Order> Orders { get; set; }
public DbSet<OrderDetail> OrderDetails { get; set; }

modelBuilder.Entity<Order>()
            .HasKey(e => e.OrderId);
modelBuilder.Entity<Order>()
            .Property(e => e.OrderId)
            .ValueGeneratedNever();
modelBuilder.Entity<Order>()
            .HasOne(o => o.Customer)
            .WithMany(c => c.Orders)
            .HasForeignKey(o => o.CustomerId);
modelBuilder.Entity<Order>()
            .HasOne(o => o.ReferralSource)
            .WithMany(r => r.Orders)
            .HasForeignKey(o => o.ReferralSourceId);
modelBuilder.Entity<Order>()
            .HasOne(o => o.StaffMember)
            .WithMany(s => s.Orders)
            .HasForeignKey(o => o.StaffId);
modelBuilder.Entity<OrderDetail>()
            .HasKey(e => e.OrderDetailId);
modelBuilder.Entity<OrderDetail>()
            .Property(e => e.OrderDetailId)
            .ValueGeneratedNever();
modelBuilder.Entity<OrderDetail>()
            .HasOne(d => d.Order)
            .WithMany(o => o.OrderDetails)
            .HasForeignKey(d => d.OrderId);
modelBuilder.Entity<OrderDetail>()
            .HasOne(o => o.Job)
            .WithOne(j => j.OrderDetail)
            .IsRequired(false)
            .HasForeignKey<Job>(jfk => jfk.OrderDetailId);

堆栈跟踪

   at Microsoft.Data.Sqlite.SqliteException.ThrowExceptionForRC(Int32 rc, sqlite3 db)
   at Microsoft.Data.Sqlite.SqliteDataReader.NextResult()
   at Microsoft.Data.Sqlite.SqliteCommand.ExecuteReader(CommandBehavior behavior)
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)

在 .NET 5.0 类库中

Microsoft.EntityFrameworkCore.Sqlite 5.01
Microsoft.EntityFrameworkCore.Proxies 5.01

我已经能够使用 SQLite 数据库编辑器输入相同的数据，因此它似乎是我的代码而不是数据。

编辑 1： 的CREATE TABLE声明OrderDetails是

CREATE TABLE [OrderDetails] (
    [OrderDetailId] text   NOT NULL COLLATE NOCASE
    ,[OrderId] text   NOT NULL COLLATE NOCASE
    ,[JobId] text   NULL COLLATE NOCASE
    ,[ItemCode] text   NOT NULL COLLATE NOCASE
    ,[ItemDescription] text   NOT NULL COLLATE NOCASE
    ,[UnitCost] numeric   NOT NULL 
    ,[NrUnits] integer   NOT NULL 
    ,[UnitPrice] numeric   NOT NULL 
    ,PRIMARY KEY ([OrderDetailId])
    FOREIGN KEY ( [OrderDetailId]) REFERENCES [Jobs]( [JobId] )

    FOREIGN KEY ( [OrderId]) REFERENCES [Orders]( [OrderId] )
);

我已经实现了Simple Logging。EF 输出的失败语句为

Failed executing DbCommand (47ms) [Parameters=[@p0='6d9d6827-df81-486f-9759-d50390dda980' (Nullable = false) (Size = 36), @p1='16' (Nullable = false) (Size = 2), @p2='Description' (Nullable = false) (Size = 11), @p3=NULL, @p4='1' (DbType = String), @p5='ef5011f6-8fa0-4483-a9bd-2a2b7de73ba6' (Nullable = false) (Size = 36), @p6='25.59' (DbType = String), @p7='44.8' (DbType = String)], CommandType='Text', CommandTimeout='30']
      INSERT INTO "OrderDetails" ("OrderDetailId", "ItemCode", "ItemDescription", "JobId", "NrUnits", "OrderId", "UnitCost", "UnitPrice")
      VALUES (@p0, @p1, @p2, @p3, @p4, @p5, @p6, @p7);

我在 SQLIte 数据库编辑器中执行相同的命令（不带参数）

INSERT INTO "OrderDetails" ("OrderDetailId", "ItemCode", "ItemDescription", "JobId", "NrUnits", "OrderId", "UnitCost", "UnitPrice")
      VALUES ('6d9d6827-df81-486f-9759-d50390dda980', '16', 'Description', NULL, '1', 'ef5011f6-8fa0-4483-a9bd-2a2b7de73ba6', '25.59', '44.8');

该行已成功输入。

如何使用 EF Core 将此订单详细信息添加到数据库中？

4

1 回答 1

0 
v11OrderDetail.Order = order;
v11OrderDetail.OrderId = order.OrderId;
order.OrderDetails.Add(v11OrderDetail);
dbase.SaveChanges();

而不是那些只做：

order.OrderDetails.Add(v11OrderDetail);
dbase.SaveChanges();

或者不要从数据库中获取订单并执行以下操作：

v11OrderDetail.OrderId = "ef5011f6-8fa0-4483-a9bd-2a2b7de73ba6";
dbase.OrderDetails.Add(v11OrderDetail);
dbase.SaveChanges();

由于您已经有了订单编号

于 2020-12-31T22:25:23.890 回答