LINQ to SQL的一对多关系

Question

过去几天我用LINQ querys表现挣扎：

LinqConnectionDataContext context = new LinqConnectionDataContext(); 
System.Data.Linq.DataLoadOptions options = new System.Data.Linq.DataLoadOptions(); 
options.LoadWith<Question>(x => x.Answers); 
options.LoadWith<Question>(x => x.QuestionVotes); 
options.LoadWith<Answer>(x => x.AnswerVotes); 
context.LoadOptions = options; 
var query =(from c in context.Questions 
      where c.UidUser == userGuid 
      && c.Answers.Any() == true 
      select new 
      { 
       c.Uid, 
       c.Content, 
       c.UidUser, 
       QuestionVote = from qv in c.QuestionVotes where qv.UidQuestion == c.Uid && qv.UidUser == userGuid select new {qv.UidQuestion, qv.UidUser }, 
       Answer = from d in c.Answers 
         where d.UidQuestion == c.Uid 
         select new 
         { 
          d.Uid, 
          d.UidUser, 
          d.Conetent, 
          AnswerVote = from av in d.AnswerVotes where av.UidAnswer == d.Uid && av.UidUser == userGuid select new { av.UidAnswer, av.UidUser } 
         } 
      }).ToList(); 

查询必须通过5000行中运行，它需要长达1分钟。我如何提高此查询的性能？

更新：

Answer 1

让你开始的东西。

CREATE PROCEDURE GetQuestionsAndAnswers 
(
    @UserGuid VARCHAR(100) 
) 
AS 
BEGIN 

SELECT 
c.Uid, 
c.Content, 
c.UidUser, 
qv.UidQuestion, 
qv.UidUser, 
av.UidAnswer, 
av.UidUser, 
av.Content, 
d.Uid, 
d.UidUser, 
d.Content 
FROM Question c 
INNER JOIN QuestionVotes qv ON qv.UidQuestion = c.Uid AND qv.UidUser = @UserGuid 
INNER JOIN Answers d ON d.UidQuestion = c.Uid 
INNER JOIN AnswerVotes av ON av.UidAnswer = d.Uid AND av.UidUser = @UserGuid 
WHERE c.UidUser = @UserGuid 

END 

您将已经聚集在默认情况下主列的索引（刚刚证实这一点在你的数据库端），以及你希望非聚集索引上QuestionVote - UidUser柱，AnswerVote - UidUser列，答案 - UidQuestion列。

也看看这里。你可能想使用.AsQueryable()而不是ToList()延期执行

Do you ToList()?

Answer 2

经过了使用sql-debug-visualizer，然后复制生成的SQL和SQL客户端运行它，看看它是如何花费的时间生成的SQL。如果需要近1分钟，你需要通过添加索引和/或存储过程或创建视图等

到imporve在数据库级性能若以上没有采取太多的时间，你可以随时创建Stored Procedure and call that using LINQ to SQ L.

还有一个建议是使用实体框架if you can change to because这是未来。