实体框架以错误的顺序插入子对象

Question

题

为什么EF首先在它所依赖的对象(TimesheetActivity)之前插入具有依赖项的子对象(PersonnelWorkRecord).还有什么我可以选择纠正这个？

ERD(简化)

这是由我直接控制的另一个系统预定义的.

EF设置和保存代码

我不确定我理解为什么/如何实体框架按照它的顺序插入我拥有的对象,但这里是我用来插入父和几个孩子的代码.

using (var db = new DataContext(user))
{
     timesheet.State = State.Added;
     timesheet.SequenceNumber = newSequenceNumber;
     this.PrepareAuditFields(timesheet);

     //To stop EF from trying to add all child objects remove them from the timehseets object.
     timesheet = RemoveChildObjects(timesheet, db);

     //Add the Timesheet object to the database context, and save.
     db.Timesheets.Add(timesheet);
     result = db.SaveChanges() > 0;
}

EF插入的SQL跟踪

当我运行代码时,我在PersonnelWorkRecord(TimesheetActivityID)上遇到SQL外键冲突,因为我还没有添加Activity(请参阅trace).

exec sp_executesql N'insert [dbo].[Timesheets]([ProjectID], [TimesheetStatusID], ...
exec sp_executesql N'insert [dbo].[PersonnelWorkdays]([TimesheetID], [PersonnelID], ...
exec sp_executesql N'insert [dbo].[PersonnelWorkRecords]([PersonnelWorkdayID],[TimesheetActivityID], ...

数据上下文摘要

modelBuilder.Entity<PersonnelWorkday>().HasRequired(pwd => pwd.Personnel).WithMany(p => p.PersonnelWorkdays).HasForeignKey(pwd => pwd.PersonnelID).WillCascadeOnDelete(false);
modelBuilder.Entity<PersonnelWorkday>().HasRequired(pwd => pwd.Timesheet).WithMany(t => t.PersonnelWorkdays).HasForeignKey(pwd => pwd.TimesheetID).WillCascadeOnDelete(false);
modelBuilder.Entity<PersonnelWorkRecord>().HasRequired(pwr => pwr.PersonnelWorkday).WithMany(pwd => pwd.PersonnelWorkRecords).HasForeignKey(pwr => pwr.PersonnelWorkdayID).WillCascadeOnDelete(false);
modelBuilder.Entity<PersonnelWorkRecord>().HasRequired(pwr => pwr.TimesheetActivity).WithMany(ta => ta.PersonnelWorkRecords).HasForeignKey(pwr => pwr.TimesheetActivityID).WillCascadeOnDelete(false);
modelBuilder.Entity<TimesheetActivity>().HasRequired(ta => ta.ProjectActivity).WithMany(a => a.TimesheetActivities).HasForeignKey(ta => ta.ProjectActivityCodeID).WillCascadeOnDelete(false);
modelBuilder.Entity<TimesheetActivity>().HasOptional(ta => ta.Facility).WithMany(f => f.TimesheetActivities).HasForeignKey(tf => tf.FacilityID).WillCascadeOnDelete(false);
modelBuilder.Entity<TimesheetActivity>().HasRequired(ta => ta.Timesheet).WithMany(t => t.TimesheetActivities).HasForeignKey(ta => ta.TimesheetID).WillCascadeOnDelete(false);

删除子对象

这是子对象方法的代码.我添加了此方法来从时间表的子对象相关对象中删除非外键的对象.例如,我有一个Crew对象,但我也有一个CrewID外键,所以我设置了Crew = null,以便EF不会尝试插入它,因为它已经存在.

private Timesheet RemoveChildObjects(Timesheet timesheet, DataContext db)
{
        timesheet.Crew = null;
        timesheet.Foreman = null;
        timesheet.Location = null;
        timesheet.Project = null;
        timesheet.SigningProjectManager = null;
        timesheet.TimesheetStatus = null;
        timesheet.Creator = null;
        timesheet.Modifier = null;

        if (timesheet.TimesheetActivities != null)
        {
            foreach (TimesheetActivity tsa in timesheet.TimesheetActivities)
            {
                tsa.Creator = null;
                if (tsa.EquipmentWorkRecords != null)
                {
                    tsa.EquipmentWorkRecords = RemoveChildObjects(tsa.EquipmentWorkRecords, db);
                }
                tsa.Facility = null;
                tsa.Modifier = null;
                if (tsa.PersonnelWorkRecords != null)
                {
                    tsa.PersonnelWorkRecords = RemoveChildObjects(tsa.PersonnelWorkRecords, db);
                }
                tsa.ProjectActivity = null;
                tsa.Structures = null;
                tsa.Timesheet = null;
            }
        }

        if (timesheet.TimesheetEquipment != null)
        {
            foreach (TimesheetEquipment te in timesheet.TimesheetEquipment)
            {
                te.Equipment = null;
                te.Timesheet = null;
            }
        }

        if (timesheet.EquipmentWorkdays != null)
        {
            timesheet.EquipmentWorkdays = RemoveChildObjects(timesheet.EquipmentWorkdays, true, db);
        }

        if (timesheet.TimesheetPersonnel != null)
        {
            foreach (TimesheetPersonnel tp in timesheet.TimesheetPersonnel)
            {
                tp.Personnel = null;
                tp.PersonnelWorkday = null;
                if (tp.PersonnelWorkday != null)
                {
                    tp.PersonnelWorkday = RemoveChildObjects(tp.PersonnelWorkday, db);
                }
                tp.Timesheet = null;
            }
        }

        if (timesheet.PersonnelWorkdays != null)
        {
            timesheet.PersonnelWorkdays = RemoveChildObjects(timesheet.PersonnelWorkdays, true, db);
        }

        return timesheet;
    }

在EF保存之前调试值

根据我的理解,当调用dbContext.Save()时,将添加/修改/删除dbContex.ObjectNameHere.Local.(取决于实体State的设置.)以下是我在调用save()并获取SQL FK异常之前尝试保存的内容. 然后我得到了FK异常.

INSERT语句与FOREIGN KEY约束"FK_PersonnelWorkRecords_TimesheetActivities"冲突.冲突发生在数据库"VPMTEST_GC",表"dbo.TimesheetActivities",列'TimesheetActivityID'中.该语句已终止.

笔记

如果有什么我可以发布以帮助描述我的问题,请告诉我.我已经浏览了google/SO以获得答案,但到目前为止还没有可靠的答案,看起来EF无法确定插入对象的顺序,除非Domain模型设置不同？我无法更改大多数对象的结构,因为它们被另一个系统使用.我可以尝试更改我的EF调用,我宁愿不使用Raw SQL,因为对象比我在这里发布的简化版本要广泛得多.

类似问题: 自引用实体和插入顺序

Answer 1

在你的RemoveChildObjects方法中我看到了这一行...

tsa.Timesheet = null;

Timesheet.TimesheetActivities所以，显然您正在设置to的反向导航属性null。您是否对PersonnelWorkRecord.TimesheetActivityand执行相同的操作，即您是否也在嵌套方法中将PersonnelWorkRecord.PersonnelWorkday这些属性设置为？nullRemoveChildObjects

这可能是一个问题，因为您有两条不同的路径从Timesheetto PersonnelWorkRecord，即：

Timesheet -> TimesheetActivities -> PersonnelWorkRecords
Timesheet -> PersonnelWorkdays -> PersonnelWorkRecords

当您调用时，db.Timesheets.Add(timesheet)我相信 EF 将一一遍历对象图中的每个分支，并确定路径上哪些相关对象（“节点”）是依赖的，哪些是关系中的主要对象，以确定插入的顺序。timesheet它本身对于所有关系都是主要的，因此很明显它必须首先插入。然后 EF 开始迭代集合之一Timesheet.TimesheetActivities或Timesheet.PersonnelWorkdays. 哪个先出现并不重要。显然 EF 以Timesheet.PersonnelWorkdays. （如果以 开头，则无法解决问题Timesheet.TimesheetActivities，您会得到相同的异常，但用PersonnelWorkRecord.PersonnelWorkday代替PersonnelWorkRecord.TimesheetActivity。）PersonnelWorkday仅取决于Timesheet已插入的内容。所以，PersonnelWorkday也可以插入。

然后 EF 继续使用 进行遍历PersonnelWorkday.PersonnelWorkRecords。关于 的PersonnelWorkday依赖关系PersonnelWorkRecord也没有问题，因为PersonnelWorkday之前已经插入了 。但是当 EF 遇到 的TimesheetActivity依赖时PersonnelWorkRecord，它会看到这TimesheetActivity是null（因为你已经将其设置为null）。现在假设依赖关系TimesheetActivityID仅由外键属性描述，该属性必须引用现有记录。它插入了PersonnelWorkRecord，这违反了外键约束。

如果PersonnelWorkRecord.TimesheetActivity不是nullEF 将检测到该对象尚未插入，但它是PersonnelWorkRecord. 因此，它可以确定必须TimesheetActivity将其插入到之前PersonnelWorkRecord。

我希望如果您不将反向导航属性设置为null- 或者至少不将PersonnelWorkRecord. （将其他导航属性（如tsa.Creator、tsa.Facility等）设置为null应该不是问题，因为这些相关对象确实已经存在于数据库中，并且您已经为它们设置了正确的 FK 属性值。）