c# - Linq to SQL 一对多关系

Question

最近几天我一直在为 linq 查询性能而苦苦挣扎:

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();

查询必须运行 5000 行，最多需要 1 分钟。我怎样才能提高这个查询的性能？

更新:

Answer 1

让您入门的东西。

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

默认情况下，您已经在主列上拥有聚集索引(只需在您的数据库端确认这一点)，并且您希望在 QuestionVote - UidUser 列、AnswerVote - UidUser 列和 Answer - UidQuestion 列上建立非聚集索引。

也可以看看这里。您可能希望使用 .AsQueryable() 而不是 ToList() 来延迟执行

Do you ToList()?