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c# - Entity Framework 在调用 INSERT 之前加载所有行

转载 作者:行者123 更新时间:2023-11-30 16:52:38 25 4
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我有一些我认为效率不高的 Entity Framework 代码。基本上,我有一个如下所示的 ApplicationUser 类:

public class ApplicationUser : IdentityUser
{
public string CompanyName { get; set; }
public virtual ICollection<SolverRun> Runs { get; set; }

// .. other stuff generated by the Visual Studio template
}

我想做的是在 SolverRuns 中为当前用户创建一个新行:

// Log run in database
var manager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new ApplicationDbContext()));
var currentUser = manager.FindById(OwnerId);
currentUser.Runs.Add(new SolverRun
{
Base = job.Base,
Duration = context.JobRunTime,
Result = (context.Result ?? "").ToString(),
RunName = job.RunName,
Start = context.FireTimeUtc.GetValueOrDefault().LocalDateTime
});

manager.Update(currentUser);

这很好用。但是,我看到的是以下查询:

exec sp_executesql N'SELECT 
[Extent1].[SolverRunID] AS [SolverRunID],
[Extent1].[RunName] AS [RunName],
[Extent1].[Base] AS [Base],
[Extent1].[Start] AS [Start],
[Extent1].[Duration] AS [Duration],
[Extent1].[Result] AS [Result],
[Extent1].[ApplicationUser_Id] AS [ApplicationUser_Id]
FROM [dbo].[SolverRuns] AS [Extent1]
WHERE ([Extent1].[ApplicationUser_Id] IS NOT NULL) AND ([Extent1].[ApplicationUser_Id] = @EntityKeyValue1)',N'@EntityKeyValue1 nvarchar(128)',@EntityKeyValue1=N'029a20a9-b487-4579-87d0-50608ed7f058'

这将为该用户选择 SolverRuns 表中的每一行。我怀疑 getter currentUser.Runs 发生了这种情况。

我担心随着用户添加越来越多的运行(最终可能有数千次),这会变得越来越慢。有没有办法只添加新行,而不是先选择所有内容?谢谢!

更新:

根据下面 py3r3str 的回答,这是我的新工作代码(在更改模型和迁移数据库等之后):

// Log run in database
using (var dbContext = new ApplicationDbContext())
{
var manager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(dbContext));
var currentUser = manager.FindById(job.OwnerId);

dbContext.Set<SolverRun>().Add(new SolverRun
{
Base = job.Base,
Duration = context.JobRunTime,
Result = (context.Result ?? "").ToString(),
RunName = job.RunName,
Start = context.FireTimeUtc.GetValueOrDefault().LocalDateTime,
ApplicationUser = currentUser
});

dbContext.SaveChanges();
}

它现在将运行此 INSERT 语句(这很奇怪,但我放弃了尝试理解 EF SQL 查询,所以我假设比我聪明的人认为它是有效的):

exec sp_executesql N'INSERT [dbo].[SolverRuns]([ApplicationUserId], [RunName], [Base], [Start], [Duration], [Result])
VALUES (@0, @1, @2, @3, @4, @5)
SELECT [SolverRunID]
FROM [dbo].[SolverRuns]
WHERE @@ROWCOUNT > 0 AND [SolverRunID] = scope_identity()',N'@0 nvarchar(128),@1 nvarchar(max) ,@2 nvarchar(max) ,@3 datetime2(7),@4 time(7),@5 nvarchar(max) ',@0=N'029a20a9-b487-4579-87d0-50608ed7f058',@1=N'PilotRun',@2=N'YUL',@3='2015-09-03 11:07:32.0353181',@4='00:00:04.1521401',@5=N'Success'

请注意,调用 currentUser.Runs 将按预期延迟加载所有运行。

最佳答案

最简单的方法之一是将外键添加到您的 SolverRun 实体:

class SolverRun
{
...
public string ApplicationUserId { get; set; }

[ForeignKey("ApplicationUserId")]
public virtual ApplicationUser ApplicationUser { get; set; }
}

并且仅使用 ApplicationContext 保存 SolverRun 实体:

var solverRun = new SolverRun
{
Base = job.Base,
Duration = context.JobRunTime,
Result = (context.Result ?? "").ToString(),
RunName = job.RunName,
Start = context.FireTimeUtc.GetValueOrDefault().LocalDateTime,
ApplicationUserId = OwnerId
};
dbContext.Set<SolverRun>().Add(solverRun);
dbContext.SaveChanges();

在这种情况下,EF 还会在 ApplicationUser.Runs 中添加对象。

关于c# - Entity Framework 在调用 INSERT 之前加载所有行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32381829/

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