实体框架6更新图 [英] Entity Framework 6 Update Graph
问题描述
什么是保存对象的状态，你不知道的图形的正确方法？由国家我的意思是，他们是否正在更新的新的或现有的数据库条目
What is the correct way to save a graph of objects whose state you don't know? By state I mean whether they are new or existing database entries that are being updated.
举例来说，如果我有：
public class Person
{
public int Id { get; set; }
public int Name { get; set; }
public virtual ICollection<Automobile> Automobiles { get; set; }
}
public class Automobile
{
public int Id { get; set; }
public int Name { get; set; }
public short Seats { get; set; }
public virtual ICollection<MaintenanceRecord> MaintenanceRecords { get; set ;}
public virtual Person Person { get; set; }
}
public class MaintenanceRecord
{
public int Id { get; set; }
public int AutomobileId { get; set; }
public DateTime DatePerformed { get; set; }
public virtual Automobile Automobile{ get; set; }
}
我编辑模式，类似上面这些对象，然后通过这些模型在数据层保存，在这种情况下我碰巧使用实体框架。所以我把这些模型转变为POCO实体内部的DAL。
I'm editing models, similar to these objects above, and then passing those models into the data layer to save, where for this instance I happen to be using entity framework. So I'm translating these models into POCO entities internal to the DAL.
看来，除非我的模型有一个状态，表明他们是否是新的或更新的，我有相当一些工作要做，以保存的转变。我必须先选择Person实体，更新它，然后匹配任何现有的汽车和更新这些，并添加任何新的，那么任何新的或更新维修记录每辆汽车检查。
It appears that unless my models have a state indicating whether they are new or updated, I have quite a bit of work to do to "Save" the changes. I have to first select the Person entity, update it, then match any existing Automobiles and update those and add any new, then for each automobile check for any new or updated maintenance records.
是否有这样做的更快/更简单的方法？这是可能的，我可以保持跟踪模型的状态，这是我的猜测是与此有帮助的，但是这将意味着改变，而我宁愿避免数据层之外的代码。我只是希望有使用模式在那里，我可以按照这样的更新。
Is there a faster/easier way of doing this? It's possible I can keep track of the Model state, which I guess would be helpful with this, but it would mean changes to code outside of the data layer which i would prefer to avoid. I'm just hoping there is a pattern of usage out there that I can follow for updates like this.
推荐答案
我跑进这个问题而回，并一直在关注的EF Codeplex上的网站这个线程。 https://entityframework.codeplex.com/workitem/864
I ran into this issue a while back and have been following this thread on the EF Codeplex site. https://entityframework.codeplex.com/workitem/864
好像它正在考虑下一个版本，我假设EF 7，这显然是EF的一个相当大的内部改革。这可能是值得一试...... http://www.nuget.org/packages/RefactorThis .GraphDiff /
Seems like it is being considered for the next release, I'm assuming EF 7, which apparently is a pretty large internal overhaul of EF. This may be worth checking out... http://www.nuget.org/packages/RefactorThis.GraphDiff/
返回的时候，我在做这个，我发现在另一个SO后EF，有人曾如何手动执行此操作的例子。那时的我决定做手工，不知道为什么，GraphDiff看起来很酷。下面是我做的一个例子。
Back when I was working on this I found another EF post on SO, and someone had an example of how to do this manually. At the time I decided to do it manually, not sure why, GraphDiff looks pretty cool. Here is an example of what I did.
public async Task<IHttpActionResult> PutAsync([FromBody] WellEntityModel model)
{
try
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
var kne = TheContext.Companies.First();
var entity = TheModelFactory.Create(model);
entity.DateUpdated = DateTime.Now;
var currentWell = TheContext.Wells.Find(model.Id);
// Update scalar/complex properties of parent
TheContext.Entry(currentWell).CurrentValues.SetValues(entity);
//We don't pass back the company so need to attached the associated company... this is done after mapping the values to ensure its not null.
currentWell.Company = kne;
// Updated geometry - ARGHHH NOOOOOO check on this once in a while for a fix from EF-Team https://entityframework.codeplex.com/workitem/864
var geometryItemsInDb = currentWell.Geometries.ToList();
foreach (var geometryInDb in geometryItemsInDb)
{
// Is the geometry item still there?
var geometry = entity.Geometries.SingleOrDefault(i => i.Id == geometryInDb.Id);
if (geometry != null)
// Yes: Update scalar/complex properties of child
TheContext.Entry(geometryInDb).CurrentValues.SetValues(geometry);
else
// No: Delete it
TheContext.WellGeometryItems.Remove(geometryInDb);
}
foreach (var geometry in entity.Geometries)
{
// Is the child NOT in DB?
if (geometryItemsInDb.All(i => i.Id != geometry.Id))
// Yes: Add it as a new child
currentWell.Geometries.Add(geometry);
}
// Update Surveys
var surveyPointsInDb = currentWell.SurveyPoints.ToList();
foreach (var surveyInDb in surveyPointsInDb)
{
// Is the geometry item still there?
var survey = entity.SurveyPoints.SingleOrDefault(i => i.Id == surveyInDb.Id);
if (survey != null)
// Yes: Update scalar/complex properties of child
TheContext.Entry(surveyInDb).CurrentValues.SetValues(survey);
else
// No: Delete it
TheContext.WellSurveyPoints.Remove(surveyInDb);
}
foreach (var survey in entity.SurveyPoints)
{
// Is the child NOT in DB?
if (surveyPointsInDb.All(i => i.Id != survey.Id))
// Yes: Add it as a new child
currentWell.SurveyPoints.Add(survey);
}
// Update Temperatures - THIS IS A HUGE PAIN = HOPE EF is updated to handle updating disconnected graphs.
var temperaturesInDb = currentWell.Temperatures.ToList();
foreach (var tempInDb in temperaturesInDb)
{
// Is the geometry item still there?
var temperature = entity.Temperatures.SingleOrDefault(i => i.Id == tempInDb.Id);
if (temperature != null)
// Yes: Update scalar/complex properties of child
TheContext.Entry(tempInDb).CurrentValues.SetValues(temperature);
else
// No: Delete it
TheContext.WellTemperaturePoints.Remove(tempInDb);
}
foreach (var temps in entity.Temperatures)
{
// Is the child NOT in DB?
if (surveyPointsInDb.All(i => i.Id != temps.Id))
// Yes: Add it as a new child
currentWell.Temperatures.Add(temps);
}
await TheContext.SaveChangesAsync();
return Ok(model);
}
catch (Exception ex)
{
Trace.WriteLine(ex.Message);
}
return InternalServerError();
}
这篇关于实体框架6更新图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
