C# 在实体框架迁移中将项目移动到项目列表

我正在使用Asp.NETMVC5和EntityFramework6。我有一张这样的桌子：

public class Recipe
{
    [Required]
    public virtual Food Food { get; set; }

    //...rest
}

public class Recipe
{
    [Required]
    public virtual Food Food { get; set; }

    public virtual IList<Food> Foods { get; set; }

    //... rest
}

现在我想把

食物

移动到食物列表中。像这样：

public class Recipe
{
    public virtual IList<Food> Foods { get; set; }

    //... rest
}

但是迁移会添加第二个外键，并且无法更新。以下是失败的迁移代码：

    public override void Up()
    {
        DropForeignKey("dbo.Recipes", "Food_ID", "dbo.Foods");
        DropIndex("dbo.Recipes", new[] { "Food_ID" });
        AddColumn("dbo.Foods", "Recipe_Id", c => c.Int());
        AddColumn("dbo.Foods", "Recipe_Id1", c => c.Int());
        AlterColumn("dbo.Recipes", "Food_ID", c => c.Int());
        CreateIndex("dbo.Foods", "Recipe_Id");
        CreateIndex("dbo.Foods", "Recipe_Id1");
        CreateIndex("dbo.Recipes", "Food_ID");
        AddForeignKey("dbo.Foods", "Recipe_Id", "dbo.Recipes", "Id");
        AddForeignKey("dbo.Foods", "Recipe_Id1", "dbo.Recipes", "Id");
        AddForeignKey("dbo.Recipes", "Food_ID", "dbo.Foods", "ID");
    }

---

如何将单个

食物

移动到

食物

列表中，而不丢失表中的当前数据？

创建迁移后，您需要自定义迁移

修改实体类

---

食谱

和

食品

之间的原始关系是什么？看起来您正在尝试从一对一（外键在

食谱

表中）转换为一对多（外键在

食品

表中）？非常感谢。工作完美无瑕。仅更正：

WHERE Foods.ID=r.Food\u ID

在您的

UPDATE

语句中。

public class Recipe
{
    public virtual IList<Food> Foods { get; set; }

    //... rest
}

public override void Up()
{
    DropForeignKey("dbo.Recipes", "Food_ID", "dbo.Foods");
    DropIndex("dbo.Recipes", new[] { "Food_ID" });
    AddColumn("dbo.Foods", "Recipe_Id", c => c.Int());

    // Update values from existing data, not sure if the syntax is perfect
    Sql(@"UPDATE dbo.Foods SET Recipe_Id = r.Id
          FROM (SELECT Id, Food_ID FROM dbo.Recipes) AS r
          WHERE Foods.ID = r.Food_ID");

    DropColumn("dbo.Recipes", "Food_ID");
    CreateIndex("dbo.Foods", "Recipe_Id");
    AddForeignKey("dbo.Foods", "Recipe_Id", "dbo.Recipes", "Id");
}