Linq2Sql Many:Many question, How would you do this?
I know many:many isn't supported in Linq2Sql but I am working on a workaround
I am working with my little SO clone and I have a table with Questions and a table with Tags and a linking table QuestionTag so I have a classic many:many relationship between Questions and Tags.
To display the list of Questions on the front page I have this class I want to fill up from a Linq2Sql query
public class ListQuestion
{
public int QuestionID { get; set; }
public string Title{ get; set; }
public IEnumerable<Tag> Tags { get; set; }
}
public IEnumerable<ListQuestion> GetQuestions()
{
from q in Questions
.................
select new ListQuestion{ ... }
}
The problem is how should I fill up the Tag collection. I found out this isn't possible to do in 1 single query so I have divided this into 2 queries, 1 to get the questions and 1 to get the tags and later try to join them. I know many:many is supported in Entity framework so how do they do it? How would you do this? Any alternative approach? The query should of course be efficient.
这可能适合你的情况;
from q in Questions
select new ListQuestion
{
Tags = q.QuestionTags.Select(qt => qt.Tag),
QuestionId = q.ID,
Title = q.Title
}
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