Is there any way to get Child elements automatically based on two parameters with Entity Framework ?

Question

Hi,

I have two Entities "Article" and "Picture", and there is a "Comment" Entity to hold the comments for any Article and Picture. (I know i can have two tables for comments, ArticleComment and PictureComment)

The Comment table structure is;

Id            numeric(18,0)   System.Long
CommentType   byte            CommentType (CommentType.Article, CommentType.Picture)
ItemId        numeric(18,0)   System.Long
Body          nvarchar(max)   string

If i had two tables for comments i mean ArticleComment and PictureComment, i just can did this

db.Article.Include("ArticleComment").FirstOrDefault(a=>a.id == articleId);

But if i just have one table for Comments i cant do this. Because i need to specify the CommentType.

I guess i could retrieve Comments for any Article or Picture entity like this ?

db.Article.Include("Comment").FirstOrDefault(a=>a.id == itemId && a.CommentType == CommentType.Article);

But there could be a problem while saving a comment because itemId can be the same on different CommentTypes (assume that Comment.ItemId is associated with Picture.Id and Article.Id in database so in EF Model)

Comment

Id     CommentType ItemId Comment
---    ----------- ------ -------
1      1           5       Comment for 5th Picture
2      2           5       Comment for 5th Article

So is it possible to hold comments in one table for two different types of Entity by the help of Custom Enum CommentType

Answer 1

Yes, it is possible exactly as you describe.