Question

我正在开发Xamarin多平台原生移动应用。我正在为数据库使用sqlite.net插件。

我创建了三个表：

public class OrderT
{
    SQLiteConnection database;

    [PrimaryKey, AutoIncrement]
    public int id { get; set; }
    public int client_id { get; set; }
    public DateTime order_date { get; set; }
}

public class OrderDetailT
{
    SQLiteConnection database;

    [PrimaryKey, AutoIncrement]
    public int id { get; set; }
    public int order_id { get; set; }
    public int quantity { get; set; }
    public float price { get; set; }
}

public class ClientT
{
    SQLiteConnection database;

    [PrimaryKey, AutoIncrement]
    public int id { get; set; }
    public string client_name { get; set; }
}

如何在Xamarin Sqlite中运行这样的查询？由于Xamarin Sqlite中没有关系和外键的概念。

SELECT OrderT.*, OrderDetailT.*, ClientT.*
FROM OrderT, OrderDetailT, ClientT
WHERE OrderT.client_id = ClientT.id AND OrderT.id = OrderDetailT.order_id

Answer 1

如何在Xamarin Sqlite中运行这样的查询？由于Xamarin Sqlite中没有关系和外键的概念

您可以使用LinQ来实现这一目标。

示例：

var list = from orderT in db.Table<OrderT>()
                  from clientT in db.Table<ClientT>()
                  from orderDetailT in db.Table<OrderDetailT>()
                  where orderT.client_id == clientT.id
                  where orderT.id == orderDetailT.order_id
                  select new { client_name=clientT.client_name, client_id = orderT.client_id, order_id = orderDetailT.order_id,price=orderDetailT.price, quality=orderDetailT.quantity };

Xamarin SQLite Net - 从多个表中获取数据

1 个答案: