Question

我正在尝试使用ServiceStack MVC PowerPack，我正在尝试使用包含的OrmLite ORM，并尝试从外键引用的表中获取数据，而不知道如何操作。

例如，在使用Northwind数据库的OrmLite示例中，是否可以将包含“ShipperTypeName”的Shipper对象作为通过外键“ShipperTypeID”查找的字符串返回？

从http://www.servicestack.net/docs/ormlite/ormlite-overview开始，如果可能的话，我想将ShipperName字段添加到Shipper类：

[Alias("Shippers")]
public class Shipper : IHasId<int>
{
    [AutoIncrement]
    [Alias("ShipperID")]
    public int Id { get; set; }

    [Required]
    [Index(Unique = true)]
    [StringLength(40)]
    public string CompanyName { get; set; }

    [StringLength(24)]
    public string Phone { get; set; }

    [References(typeof(ShipperType))]
    public int ShipperTypeId { get; set; }
}

[Alias("ShipperTypes")]
public class ShipperType : IHasId<int>
{
    [AutoIncrement]
    [Alias("ShipperTypeID")]
    public int Id { get; set; }

    [Required]
    [Index(Unique = true)]
    [StringLength(40)]
    public string Name { get; set; }
}

Answer 1

要执行此操作，您需要使用包含所需字段的Raw SQL并创建与SQL匹配的新模型，因此对于此示例，您将执行以下操作：

public class ShipperDetail
{
    public int ShipperId { get; set; }
    public string CompanyName { get; set; }
    public string Phone { get; set; }
    public string ShipperTypeName { get; set; }
}

var rows = dbCmd.Select<ShipperDetail>(
    @"SELECT ShipperId, CompanyName, Phone, ST.Name as ShipperTypeName
        FROM Shippers S INNER JOIN ShipperTypes ST 
                 ON S.ShipperTypeId = ST.ShipperTypeId");

Console.WriteLine(rows.Dump());

将输出以下内容：

[
    {
        ShipperId: 2,
        CompanyName: Planes R Us,
        Phone: 555-PLANES,
        ShipperTypeName: Planes
    },
    {
        ShipperId: 3,
        CompanyName: We do everything!,
        Phone: 555-UNICORNS,
        ShipperTypeName: Planes
    },
    {
        ShipperId: 4,
        CompanyName: Trains R Us,
        Phone: 666-TRAINS,
        ShipperTypeName: Trains
    }
]

ServiceStack.OrmLite - 如何在外键查找中包含字段？

1 个答案: