我正在运行查询以获取用户个人资料。该查询获取用户详细信息，以及他们发布的所有评论以及评论中的评论。
这可能是我试图回复太多的情况，但是随着api从移动设备调用，我宁愿在一次网络呼叫中尽可能多地获取而不是多次进行网络呼叫。
目前这会生成一些非常长的sql，大约需要25秒！
有关如何改进它的任何提示，或者投影是否是正确的方法
public UserVM GetUserInfo(string userId, string currentUserId)
{
var results =
from u in context.AspNetUsers
where u.Id == userId
select new UserVM
{
Name = u.UserName, Id = u.Id, ProfilePic = u.ProfilePicUrl, FollowerCount = u.Followers.Count, FollowingCount = u.Following.Count,
MemberSince = u.RegisteredDate,
RatingsCount = u.Ratings.Count(x => x.IsDeleted!=true),
FollowedByCurrentUser = currentUserId != null && u.Followers.Any(x => x.FollowedByUserId == currentUserId && x.UserId == userId),
reviews =
from r in u.Ratings
where r.IsDeleted != true
&& r.IsDraft != true
select new RatingVM()
{
ratingId = r.Id,
author_name = r.User.UserName,
userId = r.UserId,
profile_photo_url = r.User.ProfilePicUrl,
rating = r.RatingValue,
text = r.RatingComment,
created = r.Created,
likeCount = r.RatingLikes.Count(x => x.IsLiked && x.RatingId == r.Id),
likedByCurrentUser = currentUserId != null && r.RatingLikes.Any(x => x.IsLiked && x.RatingId == r.Id && x.UserId == currentUserId),
photos = from ri in r.RatingImages
select new PhotoVM { Id = ri.Id, width = 0, height = 0, photo_reference = ri.PhotoUrl, isMember = true, googlePlaceId = r.Place.GooglePlaceId, placeName = r.Place.Name },
comments = from c in r.Comments
where c.IsDeleted != true
select new CommentVM { commentId = c.Id, Created = c.Created, CommentText = c.CommentText, RatingId = r.Id , UserName = c.User.UserName, ProfilePicUrl = c.User.ProfilePicUrl, userId = c.UserId }
}
};
return results.FirstOrDefault();
}
SELECT
[Project17].[C1] AS [C1],
[Project17].[UserName] AS [UserName],
[Project17].[Id] AS [Id],
[Project17].[ProfilePicUrl] AS [ProfilePicUrl],
[Project17].[C32] AS [C2],
[Project17].[C33] AS [C3],
[Project17].[RegisteredDate] AS [RegisteredDate],
[Project17].[C34] AS [C4],
[Project17].[C2] AS [C5],
[Project17].[C31] AS [C6],
[Project17].[C4] AS [C7],
[Project17].[C5] AS [C8],
[Project17].[C6] AS [C9],
[Project17].[C7] AS [C10],
[Project17].[C8] AS [C11],
[Project17].[C9] AS [C12],
[Project17].[C10] AS [C13],
[Project17].[C11] AS [C14],
[Project17].[C12] AS [C15],
[Project17].[C13] AS [C16],
[Project17].[C14] AS [C17],
[Project17].[C3] AS [C18],
[Project17].[C15] AS [C19],
[Project17].[C16] AS [C20],
[Project17].[C17] AS [C21],
[Project17].[C18] AS [C22],
[Project17].[C19] AS [C23],
[Project17].[C20] AS [C24],
[Project17].[C21] AS [C25],
[Project17].[C22] AS [C26],
[Project17].[C23] AS [C27],
[Project17].[C24] AS [C28],
[Project17].[C25] AS [C29],
[Project17].[C26] AS [C30],
[Project17].[C27] AS [C31],
[Project17].[C28] AS [C32],
[Project17].[C29] AS [C33],
[Project17].[C30] AS [C34]
FROM ( SELECT
[Limit1].[Id] AS [Id],
[Limit1].[UserName] AS [UserName],
[Limit1].[ProfilePicUrl] AS [ProfilePicUrl],
[Limit1].[RegisteredDate] AS [RegisteredDate],
[Limit1].[C1] AS [C1],
[Limit1].[C2] AS [C2],
[UnionAll1].[C1] AS [C3],
[UnionAll1].[Id] AS [C4],
[UnionAll1].[Id1] AS [C5],
[UnionAll1].[C2] AS [C6],
[UnionAll1].[C3] AS [C7],
[UnionAll1].[UserId] AS [C8],
[UnionAll1].[C4] AS [C9],
[UnionAll1].[RatingValue] AS [C10],
[UnionAll1].[RatingComment] AS [C11],
[UnionAll1].[Created] AS [C12],
[UnionAll1].[C5] AS [C13],
[UnionAll1].[C6] AS [C14],
[UnionAll1].[Id2] AS [C15],
[UnionAll1].[Id3] AS [C16],
[UnionAll1].[C7] AS [C17],
[UnionAll1].[C8] AS [C18],
[UnionAll1].[PhotoUrl] AS [C19],
[UnionAll1].[C9] AS [C20],
[UnionAll1].[GooglePlaceId] AS [C21],
[UnionAll1].[Name] AS [C22],
[UnionAll1].[C10] AS [C23],
[UnionAll1].[C11] AS [C24],
[UnionAll1].[C12] AS [C25],
[UnionAll1].[C13] AS [C26],
[UnionAll1].[C14] AS [C27],
[UnionAll1].[C15] AS [C28],
[UnionAll1].[C16] AS [C29],
[UnionAll1].[C17] AS [C30],
CASE WHEN ([UnionAll1].[Id] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C31],
[Limit1].[C3] AS [C32],
[Limit1].[C4] AS [C33],
[Limit1].[C5] AS [C34]
FROM (SELECT TOP (1)
@p__linq__4 AS [p__linq__4],
@p__linq__5 AS [p__linq__5],
[Project3].[Id] AS [Id],
[Project3].[UserName] AS [UserName],
[Project3].[ProfilePicUrl] AS [ProfilePicUrl],
[Project3].[RegisteredDate] AS [RegisteredDate],
1 AS [C1],
CASE WHEN ((@p__linq__1 IS NOT NULL) AND ( EXISTS (SELECT
1 AS [C1]
FROM [dbo].[Followers] AS [Extent5]
WHERE ([Project3].[Id] = [Extent5].[UserId]) AND ([Extent5].[FollowedByUserId] = @p__linq__2) AND ([Extent5].[UserId] = @p__linq__3)
))) THEN cast(1 as bit) ELSE cast(0 as bit) END AS [C2],
[Project3].[C1] AS [C3],
[Project3].[C2] AS [C4],
[Project3].[C3] AS [C5]
FROM ( SELECT
[Project2].[Id] AS [Id],
[Project2].[UserName] AS [UserName],
[Project2].[ProfilePicUrl] AS [ProfilePicUrl],
[Project2].[RegisteredDate] AS [RegisteredDate],
[Project2].[C1] AS [C1],
[Project2].[C2] AS [C2],
(SELECT
COUNT(1) AS [A1]
FROM [dbo].[Ratings] AS [Extent4]
WHERE ([Project2].[Id] = [Extent4].[UserId]) AND (1 <> [Extent4].[IsDeleted])) AS [C3]
FROM ( SELECT
[Project1].[Id] AS [Id],
[Project1].[UserName] AS [UserName],
[Project1].[ProfilePicUrl] AS [ProfilePicUrl],
[Project1].[RegisteredDate] AS [RegisteredDate],
[Project1].[C1] AS [C1],
(SELECT
COUNT(1) AS [A1]
FROM [dbo].[Followers] AS [Extent3]
WHERE [Project1].[Id] = [Extent3].[FollowedByUserId]) AS [C2]
FROM ( SELECT
[Extent1].[Id] AS [Id],
[Extent1].[UserName] AS [UserName],
[Extent1].[ProfilePicUrl] AS [ProfilePicUrl],
[Extent1].[RegisteredDate] AS [RegisteredDate],
(SELECT
COUNT(1) AS [A1]
FROM [dbo].[Followers] AS [Extent2]
WHERE [Extent1].[Id] = [Extent2].[UserId]) AS [C1]
FROM [dbo].[AspNetUsers] AS [Extent1]
WHERE [Extent1].[Id] = @p__linq__0
) AS [Project1]
) AS [Project2]
) AS [Project3] ) AS [Limit1]
OUTER APPLY (SELECT
CASE WHEN ([Filter10].[Id1] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C1],
[Project9].[Id] AS [Id],
[Project9].[Id] AS [Id1],
[Project9].[C1] AS [C2],
[Project9].[C2] AS [C3],
[Project9].[UserId] AS [UserId],
[Project9].[C3] AS [C4],
[Project9].[RatingValue] AS [RatingValue],
[Project9].[RatingComment] AS [RatingComment],
[Project9].[Created] AS [Created],
[Project9].[C5] AS [C5],
[Project9].[C4] AS [C6],
[Filter10].[Id1] AS [Id2],
[Filter10].[Id1] AS [Id3],
CASE WHEN ([Filter10].[Id1] IS NULL) THEN CAST(NULL AS int) ELSE 0 END AS [C7],
CASE WHEN ([Filter10].[Id1] IS NULL) THEN CAST(NULL AS int) ELSE 0 END AS [C8],
[Filter10].[PhotoUrl] AS [PhotoUrl],
CASE WHEN ([Filter10].[Id1] IS NULL) THEN CAST(NULL AS bit) ELSE cast(1 as bit) END AS [C9],
[Filter10].[GooglePlaceId] AS [GooglePlaceId],
[Filter10].[Name] AS [Name],
CAST(NULL AS int) AS [C10],
CAST(NULL AS int) AS [C11],
CAST(NULL AS datetime2) AS [C12],
CAST(NULL AS varchar(1)) AS [C13],
CAST(NULL AS int) AS [C14],
CAST(NULL AS varchar(1)) AS [C15],
CAST(NULL AS varchar(1)) AS [C16],
CAST(NULL AS varchar(1)) AS [C17]
FROM (SELECT
[Project7].[Id] AS [Id],
[Project7].[RatingValue] AS [RatingValue],
[Project7].[RatingComment] AS [RatingComment],
[Project7].[Created] AS [Created],
[Project7].[PlaceId] AS [PlaceId],
[Project7].[UserId] AS [UserId],
[Limit1].[UserName] AS [C1],
N'' AS [C2],
[Limit1].[ProfilePicUrl] AS [C3],
CASE WHEN ((@p__linq__4 IS NOT NULL) AND ( EXISTS (SELECT
1 AS [C1]
FROM [dbo].[RatingLikes] AS [Extent8]
WHERE ([Project7].[Id] = [Extent8].[RatingId]) AND ([Extent8].[IsLiked] = 1) AND ([Extent8].[RatingId] = [Project7].[Id]) AND ([Extent8].[UserId] = @p__linq__5)
))) THEN cast(1 as bit) ELSE cast(0 as bit) END AS [C4],
[Project7].[C1] AS [C5]
FROM ( SELECT
[Project6].[Id] AS [Id],
[Project6].[RatingValue] AS [RatingValue],
[Project6].[RatingComment] AS [RatingComment],
[Project6].[Created] AS [Created],
[Project6].[PlaceId] AS [PlaceId],
[Project6].[UserId] AS [UserId],
(SELECT
COUNT(1) AS [A1]
FROM [dbo].[RatingLikes] AS [Extent7]
WHERE ([Project6].[Id] = [Extent7].[RatingId]) AND ([Extent7].[IsLiked] = 1) AND ([Extent7].[RatingId] = [Project6].[Id])) AS [C1]
FROM ( SELECT
[Extent6].[Id] AS [Id],
[Extent6].[RatingValue] AS [RatingValue],
[Extent6].[RatingComment] AS [RatingComment],
[Extent6].[Created] AS [Created],
[Extent6].[PlaceId] AS [PlaceId],
[Extent6].[UserId] AS [UserId]
FROM [dbo].[Ratings] AS [Extent6]
WHERE ([Limit1].[Id] = [Extent6].[UserId]) AND (1 <> [Extent6].[IsDeleted]) AND (1 <> [Extent6].[IsDraft])
) AS [Project6]
) AS [Project7] ) AS [Project9]
OUTER APPLY (SELECT [Extent9].[Id] AS [Id1], [Extent9].[PhotoUrl] AS [PhotoUrl], [Project10].[Name] AS [Name], [Project10].[GooglePlaceId] AS [GooglePlaceId]
FROM [dbo].[RatingImages] AS [Extent9]
LEFT OUTER JOIN (SELECT
[Extent10].[Id] AS [Id],
[Extent10].[Name] AS [Name],
[Extent10].[GooglePlaceId] AS [GooglePlaceId]
FROM [dbo].[Places] AS [Extent10]
WHERE [Project9].[PlaceId] = [Extent10].[Id] ) AS [Project10] ON 1 = 1
WHERE [Project9].[Id] = [Extent9].[RatingId] ) AS [Filter10]
UNION ALL
SELECT
2 AS [C1],
[Project15].[Id] AS [Id],
[Project15].[Id] AS [Id1],
[Project15].[C1] AS [C2],
[Project15].[C2] AS [C3],
[Project15].[UserId] AS [UserId],
[Project15].[C3] AS [C4],
[Project15].[RatingValue] AS [RatingValue],
[Project15].[RatingComment] AS [RatingComment],
[Project15].[Created] AS [Created],
[Project15].[C5] AS [C5],
[Project15].[C4] AS [C6],
CAST(NULL AS int) AS [C7],
CAST(NULL AS int) AS [C8],
CAST(NULL AS int) AS [C9],
CAST(NULL AS int) AS [C10],
CAST(NULL AS varchar(1)) AS [C11],
CAST(NULL AS bit) AS [C12],
CAST(NULL AS varchar(1)) AS [C13],
CAST(NULL AS varchar(1)) AS [C14],
[Join2].[Id2] AS [Id2],
[Join2].[Id2] AS [Id3],
[Join2].[Created] AS [Created1],
[Join2].[CommentText] AS [CommentText],
[Project15].[Id] AS [Id4],
[Join2].[UserName] AS [UserName],
[Join2].[ProfilePicUrl] AS [ProfilePicUrl],
[Join2].[UserId] AS [UserId1]
FROM (SELECT
[Project13].[Id] AS [Id],
[Project13].[RatingValue] AS [RatingValue],
[Project13].[RatingComment] AS [RatingComment],
[Project13].[Created] AS [Created],
[Project13].[UserId] AS [UserId],
[Limit1].[UserName] AS [C1],
N'' AS [C2],
[Limit1].[ProfilePicUrl] AS [C3],
CASE WHEN ((@p__linq__4 IS NOT NULL) AND ( EXISTS (SELECT
1 AS [C1]
FROM [dbo].[RatingLikes] AS [Extent13]
WHERE ([Project13].[Id] = [Extent13].[RatingId]) AND ([Extent13].[IsLiked] = 1) AND ([Extent13].[RatingId] = [Project13].[Id]) AND ([Extent13].[UserId] = @p__linq__5)
))) THEN cast(1 as bit) ELSE cast(0 as bit) END AS [C4],
[Project13].[C1] AS [C5]
FROM ( SELECT
[Project12].[Id] AS [Id],
[Project12].[RatingValue] AS [RatingValue],
[Project12].[RatingComment] AS [RatingComment],
[Project12].[Created] AS [Created],
[Project12].[UserId] AS [UserId],
(SELECT
COUNT(1) AS [A1]
FROM [dbo].[RatingLikes] AS [Extent12]
WHERE ([Project12].[Id] = [Extent12].[RatingId]) AND ([Extent12].[IsLiked] = 1) AND ([Extent12].[RatingId] = [Project12].[Id])) AS [C1]
FROM ( SELECT
[Extent11].[Id] AS [Id],
[Extent11].[RatingValue] AS [RatingValue],
[Extent11].[RatingComment] AS [RatingComment],
[Extent11].[Created] AS [Created],
[Extent11].[UserId] AS [UserId]
FROM [dbo].[Ratings] AS [Extent11]
WHERE ([Limit1].[Id] = [Extent11].[UserId]) AND (1 <> [Extent11].[IsDeleted]) AND (1 <> [Extent11].[IsDraft])
) AS [Project12]
) AS [Project13] ) AS [Project15]
INNER JOIN (SELECT [Extent14].[Id] AS [Id2], [Extent14].[CommentText] AS [CommentText], [Extent14].[Created] AS [Created], [Extent14].[RatingId] AS [RatingId], [Extent14].[IsDeleted] AS [IsDeleted], [Extent14].[UserId] AS [UserId], [Extent15].[UserName] AS [UserName], [Extent15].[ProfilePicUrl] AS [ProfilePicUrl]
FROM [dbo].[Comments] AS [Extent14]
INNER JOIN [dbo].[AspNetUsers] AS [Extent15] ON [Extent14].[UserId] = [Extent15].[Id] ) AS [Join2] ON ([Project15].[Id] = [Join2].[RatingId]) AND (1 <> [Join2].[IsDeleted])) AS [UnionAll1]
) AS [Project17]
ORDER BY [Project17].[Id] ASC, [Project17].[C31] ASC, [Project17].[C5] ASC, [Project17].[C3] ASC
答案 0 :(得分：2)
EF6的每个LINQ查询使用一个大SQL查询的加载策略对于加载复杂对象图不是最佳选择。还有其他几种方法可以加载图表。
例如，您可以加载根AspNetUser实体，然后遍历导航属性以构建图形。 EF会根据需要进行延迟加载。一旦实体在上下文中缓存，后续导航就不会导致其他查询。
事实上，如果您预先获取部分或全部相关实体，EF将“缝合”或“修复”您的导航属性。
因此，作为优化，您可以使用一些简单且便宜的查询编写查询，以获取您将需要的实体。
类似
var user = context.AspNetUsers.Where(u => u.Id == userId).Single();
var followers = context.Followers.Where(f => f.UserId == userId).ToList();
var ratings = context.Ratings.Where(f => f.UserId == userId).ToList();
var ratingIds = ratings.Select(r => r.Id).ToList();
var ratingLikes = context.RatingLikes.Where(x => ratingIds.Contains(x.RatingId) && x.IsLiked ).ToList();
var ratingPhotos = context.RatingPhotos.Where(x => ratingIds.Contains(x.RatingId)).ToList();
然后从加载的AspNetUser构建结果，例如
var u = user;
var results =
select new UserVM
{
Name = u.UserName,
Id = u.Id,
ProfilePic = u.ProfilePicUrl,
FollowerCount = u.Followers.Count, . . .