如何覆盖 Entity Framework Core 6 中的外键列？

Question

我正在使用 Entity Framework Core 6。我在 SQL 服务器中有 3 个表， order ， orderitem和product 。

order表的主键是id ， orderitem的外键是orderid和product_id 。 一切都设置正确，但是，EF Core 6 生成的查询没有使用product_id ，而是继续使用productId作为 map 到product表的外键。 覆盖它的最佳位置在哪里？

这是错误部分：

FROM [ShipEngineOrderItems] AS [s0]   
LEFT JOIN [Products] AS [p] ON [s0].[ProductId] = [p].[Id]

这是完整的错误消息，上面的 select 语句使用正确的列名

Microsoft.EntityFrameworkCore.Database.Command[20102]
执行 DbCommand (90ms) 失败 [Parameters=[@__orderId_0='?' (DbType = Int32)]，CommandType='Text'，CommandTimeout='30']
SELECT [s].[id], [s].[order_date], [t].[PId], [t].[ProductName], [t].[Price], [t].[id], [ t].[Id0]
FROM [ShipEngineOrders] AS [s]
左连接（
SELECT [s0].[product_id] AS [PId], [p].[WarehouseSku] AS [ProductName], [s0].[price] AS [Price], [s0].[id], [p].[ Id] AS [Id0], [s0].[orderId]
从 [ShipEngineOrderItems] 作为 [s0]
左连接 [Products] AS [p] ON [s0].[ProductId] = [p].[Id]
) AS [t] ON [s].[id] = [t].[orderId]
WHERE [s].[id] = @__orderId_0
按 [s].[id]、[t].[id] 排序

失败：Microsoft.EntityFrameworkCore.Query[10100]

迭代上下文类型“Core.Data.ApplicationDbContext”的查询结果时发生异常。
Microsoft.Data.SqlClient.SqlException (0x80131904)：列名“ProductId”无效。

这是我的代码：

public partial class Order
{
    public int id { get; set; }
    public DateTime order_date { get; set; }
    public virtual ICollection<OrderItem> OrderItems { get; set; }
}

public partial class OrderItem
{
    public int id { get; set; }
    [Column(TypeName = "decimal(18,2")]
    public decimal price { get; set; }
    public int orderId { get; set; } // navigation property
    public virtual Order Order { get; set; }
    [Column("product_id")]
    public int product_id { get; set; } // navigation property
    public virtual Product Product { get; set; }
}

public partial class Product
{
   public int Id { get; set; }
   public string? WarehouseSku { get; set; } 
}

public class ApplicationDbContext : DbContext
{
    public ApplicationDbContext() { }
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : 
    base(options) { }

    public virtual DbSet<Order> Order { get; set; }
    public virtual DbSet<OrderItem> OrderItem { get; set; }
    public virtual DbSet<Product> Product { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Order>()
           .ToTable("ShipEngineOrders", t => t.ExcludeFromMigrations());

        //modelBuilder.Entity<OrderItem>()
        //    .Property(i => i.product_id).HasColumnName("product_id");

        modelBuilder.Entity<OrderItem>()
           .ToTable("ShipEngineOrderItems", t => t.ExcludeFromMigrations());
        
        modelBuilder.Entity<Product>()
            .ToTable("Products", t => t.ExcludeFromMigrations());
    }
}

非常感谢您的建议

Answer 1

使用 Fluent API 作为参考。 添加这两个参考

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;


public partial class OrderItem
{
    public int id { get; set; }
    [Column(TypeName = "decimal(18,2")]
    public decimal price { get; set; }
    [ForeignKey("Order")] // add foreign key reference here
    public int orderId { get; set; } // navigation property
    public virtual Order Order { get; set; }
    [Column("product_id")]
    [ForeignKey("Product")] //This is the foreign key reference
    public int product_id { get; set; } // navigation property
    public virtual Product Product { get; set; }
    public virtual Order Order{ get; set; }
}

此外，尝试实践约定优于配置。 如果您的数据库设计使用 ProductId 而不是 product_id。 外键配置是自动设置的。这同样适用于 OrderId 而不是 orderId