Question

Table 1: Articles

Table 2: ArticleCategories

how do I represent the relationship between the two tables which is a 1->1 relationship:

I can do the following, but I’m not sure it’s the correct way :

public class Article
{
    public int ArticleIndex { get; set; }
    public int Category { get; set; }
    public Guid User { get; set; }
    public int Parent { get; set; }
    public int Level { get; set; }
    public int Order { get; set; }
    public DateTime DateCreated { get; set; }
    public DateTime DateExpires { get; set; }
    public bool Show { get; set; }   
    public string Title { get; set; }
    public string TitleHtml { get; set; }
    public string Content { get; set; }
    public string ContentHtml { get; set; }
    public string ShortTitle { get; set; }
    public ArticleCategory Category { get; set; }
}

public class ArticleCategory
{
    public int CategoryIndex { get; set; }
    public string Name { get; set; }
}

Answer 1

By convention, Code First expects an Id property for each class/table. Then you can do something like this:

public class Article
{
    public int Id { get; set; }
    public int ArticleIndex { get; set; }
    public int Category { get; set; }
    public Guid User { get; set; }
    public int Parent { get; set; }
    public int Level { get; set; }
    public int Order { get; set; }
    public DateTime DateCreated { get; set; }
    public DateTime DateExpires { get; set; }
    public bool Show { get; set; }   
    public string Title { get; set; }
    public string TitleHtml { get; set; }
    public string Content { get; set; }
    public string ContentHtml { get; set; }
    public string ShortTitle { get; set; }
    public int ArticleCategoryId { get; set; }

    public virtual ArticleCategory ArticleCategory { get; set; }
}

public class ArticleCategory
{
    public int Id { get; set; }
    public int CategoryIndex { get; set; }
    public string Name { get; set; }

    public virtual ICollection<Article> Articles { get; set; }
}

Note the virtual keyword. EF Code First needs this so it can perform its magic behind the scenes.

Now, if you are working with an Article, you can get all it’s category info by doing article.ArticleCategory, and if you have an ArticleCategory you can find out what article it refers to with articleCategory.Articles.Single().

For more info, see this article by Scott Gu:

http://weblogs.asp.net/scottgu/archive/2010/12/08/announcing-entity-framework-code-first-ctp5-release.aspx