entity-framework - EF Code First: INSERT ステートメントが FOREIGN KEY 制約と競合しました

Question

これは、breeze/angular/EF を使用した私のトライアル プロジェクトです。以前と同じ構造が機能していると思っていたので、なぜこのエラーが発生するのかわかりません。

public class TshirtOrder
{
    public int Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<OrderItem> OrderItems { get; set; }
}

public class OrderItem
{
    public int Id { get; set; }
    [ForeignKey("Type")]
    public int TshirtTypeId { get; set; }
    public virtual TshirtType Type { get; set; }
    [ForeignKey("Size")]
    public int TshirtSizeId { get; set; }
    public virtual TshirtSize Size { get; set; }
    public double UnitPrice { get; set; }
    public int Quantity { get; set; }

    [ForeignKey("TshirtOrder")]
    public int TshirtOrderId { get; set; }
    public TshirtOrder TshirtOrder { get; set; }
}

テーブル定義は次のようになります。

CREATE TABLE [dbo].[TshirtOrder] (
    [Id]         INT            IDENTITY (1, 1) NOT NULL,
    [Name]       NVARCHAR (MAX) NULL,
    CONSTRAINT [PK_dbo.TshirtOrder] PRIMARY KEY CLUSTERED ([Id] ASC)
);

CREATE TABLE [dbo].[OrderItem] (
    [Id]            INT        IDENTITY (1, 1) NOT NULL,
    [TshirtTypeId]  INT        NOT NULL,
    [TshirtSizeId]  INT        NOT NULL,
    [UnitPrice]     FLOAT (53) NOT NULL,
    [Quantity]      INT        NOT NULL,
    [TshirtOrderId] INT        NOT NULL,
    CONSTRAINT [PK_dbo.OrderItem] PRIMARY KEY CLUSTERED ([Id] ASC),
    CONSTRAINT [FK_dbo.OrderItem_dbo.TshirtType_TshirtTypeId] FOREIGN KEY ([TshirtTypeId]) REFERENCES [dbo].[TshirtType] ([Id]) ON DELETE CASCADE,
    CONSTRAINT [FK_dbo.OrderItem_dbo.TshirtSize_TshirtSizeId] FOREIGN KEY ([TshirtSizeId]) REFERENCES [dbo].[TshirtSize] ([Id]) ON DELETE CASCADE,
    CONSTRAINT [FK_dbo.OrderItem_dbo.TshirtOrder_TshirtOrderId] FOREIGN KEY ([TshirtOrderId]) REFERENCES [dbo].[TshirtOrder] ([Id]) ON DELETE CASCADE
);

Breeze データコンテキストに保存される方法は次のとおりです。

function _createTshirtOrder() {
    var order = manager.createEntity("TshirtOrder");

    order.orderItems.push(createOrderItem(lookups.tshirtTypes[0], lookups.tshirtSizes[0], 10));
    common.saveEntity(order);
    return order;

    function createOrderItem(type, size, unitPrice) {
        var item = manager.createEntity("OrderItem");
        item.type = type;
        item.size = size;
        item.unitPrice = unitPrice;
        item.quantity = 0;
        return item;
    }
}

正確なエラーは次のとおりです。

{"The INSERT statement conflicted with the FOREIGN KEY constraint \"FK_dbo.OrderItem_dbo.TshirtOrder_TshirtOrderId\". The conflict occurred in database \"dbbb\", table \"dbo.TshirtOrder\", column 'Id'.\r\nThe statement has been terminated."}

では、どこに問題があるのでしょうか。