Question

我有以下表格

客户表和产品表

ID
Name

ClientProduct表

ID
ClientID
ProductID

产品类

 private int id;
    public int ID
    {
        get { return id; }
        set { id = value; }
    }
     protected string name;

    public Product () { }

    public Product (string name)
    {
        this.name = name;
    }

    public Product (string name)
    {
        this.name = name;
    }   
    public string Name
    {
        get { return name; }
        set { name = value; }
    }

客户端类

     private int id;
    public int ID
    {
        get { return id; }
        set { id = value; }
    }
     protected string name;

    public Client () { }

    public Client (string name)
    {
        this.name = name;
    }

    public Client (string name)
    {
        this.name = name;
    }   
    public string Name
    {
        get { return name; }
        set { name = value; }
    }

ClientProduct类

        protected Client client;
    protected Product product;

    public ClientProduct  () { }

    public ClientProduct  (Client client,  Product product)
    {
        this.client= client;
        this.product= product;
    }

    public Client client        {
        get { return client; }
        set { client= value; }
    }

    public Product product      {
        get { return product; }
        set { product= value; }
    }

如何在petaPOCO中执行以下操作？

    public static System.Collections.Generic.IList<ClientProduct> LoadForClient(Client client)
    {
        if (null != client)
            return Load("ClientID = " + client.ID);
        else
            return null;
    }

这样我就可以获得该客户端的所有产品列表，我将在以后的视图中用作

 private void LoadProducts(Client client )
    {
        Products = ClientProduct.LoadForClient(client)
            .Select(x => x.Product.Name)
            .OrderBy(x => x).ToArray();
    }

Answer 1

1：M和M：1的关系看起来就像你追求的那样 http://www.toptensoftware.com/Articles/115/PetaPoco-Mapping-One-to-Many-and-Many-to-One-Relationships

您可以定义自定义关联回调; Brad的两个表的示例（如果您的产品直接映射到客户端）看起来像这样：

var posts = db.Fetch<Product, Client, ClientProduct>(
    (p,c)=> { p.client_obj = c; return p; },
    @"SELECT * FROM Product
    LEFT JOIN Client ON Product.clientId = Client.id ORDER BY Product.clientId 
    ");

我意识到你处理M：M关系所以你需要更新上面的内容来映射三个对象，但概念是相同的。关键是调用中的第三个参数（ClientProduct）代表连接的行，然后您可以直接从单个列表中引用客户端和/或产品。

处理不直接映射到数据库上的列的属性

1 个答案: