Question

我有一张表'Article'

private int id;
    [ColumnAttribute(Storage = "id", AutoSync = AutoSync.OnInsert, DbType = "Int NOT NULL IDENTITY", IsPrimaryKey = true, IsDbGenerated = true)]
    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    private string title;
    [ColumnAttribute(Storage = "title", DbType = "NVarChar(250) NOT NULL", CanBeNull = false)]
    public string Title
    {
        get { return title; }
        set { title = value; }
    }

    private string description;
    [ColumnAttribute(Storage = "description", DbType = "NVarChar(350) NOT NULL", CanBeNull = false)]
    public string Description
    {
        get { return description; }
        set { description = value; }
    }

和表评论

 [Table(Name = "dbo.Comments")]
public class CommentDto
{
    private int id;
    [ColumnAttribute(Storage = "id", AutoSync = AutoSync.OnInsert, DbType = "Int NOT NULL IDENTITY", IsPrimaryKey = true, IsDbGenerated = true)]
    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    private string content;
    [ColumnAttribute(Storage = "content", DbType = "NVarChar(600) NOT NULL", CanBeNull = false)]
    public string Content
    {
        get { return content; }
        set { content = value; }
    }

    private string date;
    [ColumnAttribute(Storage = "date", DbType = "DateTime NOT NULL", CanBeNull = false)]
    public string Date
    {
        get { return date; }
        set { date = value; }
    }
}

一篇文章可以有很多评论，每个评论都可以由用户放置

[TableAttribute(Name = "dbo.Users")]
public class UserDto
{
    private int id;
    [ColumnAttribute(Storage = "id", AutoSync = AutoSync.OnInsert, DbType = "Int NOT NULL IDENTITY", IsPrimaryKey = true, IsDbGenerated = true)]
    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    private string username;
    [ColumnAttribute(Storage = "username", DbType = "NVarChar(150) NOT NULL", CanBeNull = false)]
    public string Username
    {
        get { return username; }
        set { username = value; }
    }

如何映射这些表之间的关系？

由于

Answer 1

我认为您是手动创建表类。没有必要这样做。

将LINQ to SQL（dbml）文件添加到您的解决方案中，打开“服务器资源管理器”窗口并连接到您的数据库，将表拖放到dbml类的设计中。

如果表中存在外键约束，则链接将在两个类中创建相应的属性。

如果你想手动完成（我不明白为什么），使用引用类的类型创建一个属性，这是所需的属性：

[Association(Name="your_fk_constraint_name", Storage="name_of_your_private_backup_field", ThisKey="name_of_the_key_in_this_table", IsForeignKey=true)]

希望我能帮助一点

Answer 2

您可以阅读有关映射关联here的信息。

在你的情况下：

class Article
{
    private EntitySet<CommentDto> _Comments;

    [Association(OtherKey = "ArticleID")]
    public virtual IList<CommentDto> Comments
    {
            get
            {
                if (_Comments == null)
                    _Comments = new EntitySet<CommentDto>();
                return _Comments;
            }
            set
            {
                Comments.Assign(value);
            }
    }
}

class Comment
{
    [Association(ThisKey="ArticleID")]
    public ArticleDto Article { get; set; }
}

当然，您应首先将ArticleID列添加到数据库中的“注释”表。

以下部分未在上面链接的MSDN代码中显示，但没有它我在WCF服务中遇到了很多DTO问题。所以，现在我更愿意将它添加到每个协会：

if (_Comments == null)
    _Comments = new EntitySet<CommentDto>();

如何使用Linq映射到SQL一对多

2 个答案: