Question

I use EntityFramework and need assistance with LINQ query.
Im building an application that will store articles.
Same article can be translated to many languages.
So I have 2 tables:

Article table:

ArticleId
ResourceTitleId   (FK: LocalizedContent.ResourceId)
ResourceContentId (FK: LocalizedContent.ResourceId)

LocalizedContent table:

ResourceId
LanguageId
Content

So, for sake of example, if I have article in English and Russian,
I would store one row in Article table which would look like that:

 ArticleId | ResourceTitleId | ResourceContentId |
-----------|-----------------|-------------------|
          1|               1 |                 2 |

And then, LocalizedContent table will look like this:

 ResourceId | LanguageId | Content |
------------|------------|---------|
           1|          1 |     aaa |
------------|------------|---------|
           1|          2 |     zzz |
------------|------------|---------|
           2|          1 |     bbb |
------------|------------|---------|
           2|          2 |     yyy |

And now for the question:
I want to select an article by language id (lets say English), and I want my result to look like that:

 ArticleId | ResourceTitle | ResourceContent |
-----------|---------------|-----------------|
          1|           aaa |             bbb |

How do I perform LINQ query that will retrieve me that result in one query?

Answer 1

Just perform an inner join between the two tables filtering them by LanguageId.

var english = 1;
var query =
    from article in dc.Articles
    join resourceTitle in dc.LocalizedContent
        on article.ResourceTitleId equals resourceTitle.ResourceId
    join resourceContent in dc.LocalizedContent
        on article.ResourceContentId equals resourceContent.ResourceId
    where resourceTitle.LanguageId == english
       && resourceContent.LanguageId == english
    select new
    {
        article.ArticleId,
        ResourceTitle = resourceTitle.Content,
        ResourceContent = resourceContent.Content,
    };