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Attach entities with tree to EF

I have a huge form with many child entities, so, I fill EF object with tree using Automapper. Then I want to update similar entities in DB. Any way to attach its to context?
I try to do it by way:
// ApplicationDriver has many child objects
Infrastructure.Asset.ApplicationDriver driver = mapper.Map<Infrastructure.Asset.ApplicationDriver>(model);
// get similar object from DB
Infrastructure.Asset.ApplicationDriver currentApplication = db.ApplicationDrivers.Where(p => p.ApplicationId == model.ApplicationId).FirstOrDefault();
if (currentApplication == null)
{
db.ApplicationDrivers.Add(driver);
}
else
{
// try to attach driver to current context.
// I want to 'replace' current object with all child objects in DB
db.ApplicationDrivers.Attach(driver);
currentApplication = driver;
}
await db.SaveChangesAsync();
I get an error:
"Attaching an entity of type 'Infrastructure.Asset.ApplicationDriver'
failed because another entity of the same type already has the same
primary key value. This can happen when using the 'Attach' method or
setting the state of an entity to 'Unchanged' or 'Modified' if any
entities in the graph have conflicting key values. This may be because
some entities are new and have not yet received database-generated key
values. In this case use the 'Add' method or the 'Added' entity state
to track the graph and then set the state of non-new entities to
'Unchanged' or 'Modified' as appropriate."
I try:
var currentApplication = db.ApplicationDrivers.Where(p => p.ApplicationId == model.ApplicationId).FirstOrDefault();
if (currentApplication == null)
{
db.ApplicationDrivers.Add(driver);
}
else
{
driver.Id = currentApplication.Id;
db.ApplicationDrivers.Attach(driver);
}
await db.SaveChangesAsync();
and get the same error. What is incorrect and how to solve this problem without manual copying each property for all child objects from driver to currentApplication?

No need to attach to entity, if you want to update the DB, and replace the db with the current object :
// ApplicationDriver has many child objects
Infrastructure.Asset.ApplicationDriver driver = mapper.Map<Infrastructure.Asset.ApplicationDriver>(model);
// get similar object from DB
Infrastructure.Asset.ApplicationDriver currentApplication = db.ApplicationDrivers.Where(p => p.ApplicationId == model.ApplicationId).FirstOrDefault();
if (currentApplication == null)
{
db.ApplicationDrivers.Add(driver);
}
else
{
//this will attach, and set state to modified
//same as previous question, make sure you virtual properties are not populated to avoid unwanted duplicates.
db.Entry(driver).State = System.Data.Entity.EntityState.Modified;
currentApplication = driver;
}
await db.SaveChangesAsync();

I have found an article:
https://www.devtrends.co.uk/blog/stop-using-automapper-in-your-data-access-code
seems, it would better don't use automapper to map DTO to EF for edit case..

EF: how to modify existing entry in DB in N-layered application

Im not EF specialist propably, but I have an issue with it:).
Im doing n-layered business application, so I have Service code and Repository code in my app. In my service code, it read existing User entity, I do update of some properties and it calls Repositiry' method Edit. And there error appears:
Attaching an entity of type
'MobileWallet.Common.Repository.MwbeUserData' failed because another
entity of the same type already has the same primary key value. This
can happen when using the 'Attach' method or setting the state of an
entity to 'Unchanged' or 'Modified' if any entities in the graph have
conflicting key values. This may be because some entities are new and
have not yet received database-generated key values. In this case use
the 'Add' method or the 'Added' entity state to track the graph and
then set the state of non-new entities to 'Unchanged' or 'Modified' as
appropriate.
My Edit method looks like this:
public override void Edit(MwbeUserData entityToUpdate)
{
LogChangeTrackerStateValues("UserUpdate starts");
if (Context.Entry(entityToUpdate).State == EntityState.Detached)
{
DbSet.Attach(entityToUpdate);
}
Context.Entry(entityToUpdate).State = EntityState.Modified;
//fix for User.Address problem
Context.Entry(entityToUpdate.Address).State = EntityState.Modified;
LogChangeTrackerStateValues("UserUpdate ends");
}
I also tried code like this:
public override void Edit(MwbeUserData entityToUpdate)
{
Context.Entry(entityToUpdate).State = EntityState.Modified;
//fix for User.Address problem
Context.Entry(entityToUpdate.Address).State = EntityState.Modified;
}
Record which it being udpated is kept in ChangeTracker
Context.ChangeTracker.Entries().ToList()[1]
but Context.Entry(entityToUpdate).State = Detach for this object.
QUESTION 1: How to solve this?
QUESTION 2: Any good tutorial to understand how to work with EF with business n-layered applications?
Thanks for answers.
UPDATE 1:
New findings:
In Repository Edit method:
Context.ChangeTracker.Entries().ToList()[1].CurrentValues["Firstname"] = "AAA"
Context.ChangeTracker.Entries().ToList()[1].OriginalValues["Firstname"]= "AAA"
but CurrentValue should be BBB, why is not updated? it was updated in Service code which calls Respority Code and updated entity is passed to Repository Edit method.
UPDATE 2:
More about my architecture: I have 3 layes Controler(WEB API), Service and Repository. So my Service method update looks like this:
public bool UpdateUser(MwbeUserUpdateIn userUpdateData)
{
MwbeReturnData<MwbeUserData> userData = repository.Get(userUpdateData.UserId);
// Determine if user exists
if (MwbeResponseCodes.NotFound == userData.Code)
{
return false;
}
MwbeUserData user = userData.Data;
// Check each field to be updated
if (!String.IsNullOrEmpty(userUpdateData.FirstName))
{
user.Firstname = userUpdateData.FirstName;
}
if (!String.IsNullOrEmpty(userUpdateData.MiddleName))
{
user.Middlename = userUpdateData.MiddleName;
}
if (!String.IsNullOrEmpty(userUpdateData.LastName))
{
user.Secondname = userUpdateData.LastName;
}
if (!String.IsNullOrEmpty(userUpdateData.MobileNumber))
{
user.Mobilenumber = userUpdateData.MobileNumber;
}
if (!String.IsNullOrEmpty(userUpdateData.Email))
{
user.Email = userUpdateData.Email;
}
if (null != userUpdateData.BirthDate)
{
user.BirthDate = (DateTime)userUpdateData.BirthDate;
}
// Update Addres fields
if (null != userUpdateData.Address)
{
if (!String.IsNullOrEmpty(userUpdateData.Address.City))
{
user.Address.City = userUpdateData.Address.City;
}
if (!String.IsNullOrEmpty(userUpdateData.Address.Country))
{
user.Address.Country = userUpdateData.Address.Country;
}
if (!String.IsNullOrEmpty(userUpdateData.Address.Street))
{
user.Address.Street = userUpdateData.Address.Street;
}
if (!String.IsNullOrEmpty(userUpdateData.Address.ZipCode))
{
user.Address.ZipCode = userUpdateData.Address.ZipCode;
}
}
// Save changes to DB
repository.Edit(ref user);
repository.SaveChanges();
return true;
}

Instead of calling Context.Entry(entityToUpdate) and setting it state to modified you could search for the entity you want to update and modify its members. Then set its state as modified, like this.
Also in your Edit function you should explicitly list which members of your MwbeUserData object your are updating. This is a security issue, it will prevent someone over posting extra members to your controller.
Here is an example of a edit function I have used.
public ActionResult Edit([Bind(Include = "Id,CompanyName,Abbreviation,CompanyTypeRef")] Company company)
{
if (!ModelState.IsValid) return View(company);//error invalid state
var c = Entities.Set<Company>().FirstOrDefault(x => x.Id == company.Id);
if(c == null) return View(company);// error could not find entity
Entities.Entry(c).CurrentValues.SetValues(company);
Entities.Entry(c).State = EntityState.Modified;
Entities.SaveChanges();
return RedirectToAction("Edit", "Company", new { id = company.Id });
}
Update:
I had a similar issue with entity changes not being recorded by changes tracker in EntityFramework.Extented and it was fix by updating the entities CurrentValues with this line.
Entities.Entry(c).CurrentValues.SetValues(company);

Updating existing data in EF 6 throws exception - "...entity of the same type already has the same primary key value."

I am trying to update a record using Entity Framework 6, code-first, no fluent mapping or a tool like Automapper.
The entity(Employee) has other composite properties associated with it like Addreess(collection), Department
It is also inherited from a base called User
The save method is as follows, with _dbContext being the DbConext implementation
public bool UpdateEmployee(Employee employee)
{
var entity = _dbContext.Employees.Where(c => c.Id == employee.Id).AsQueryable().FirstOrDefault();
if (entity == null)
{
_dbContext.Employees.Add(employee);
}
else
{
_dbContext.Entry(employee).State = EntityState.Modified; // <- Exception raised here
_dbContext.Employees.Attach(employee);
}
return _dbContext.SaveChanges() > 0;
}
I keep getting the error:
Attaching an entity of type failed because another entity of the same
type already has the same primary key value. This can happen when
using the 'Attach' method or setting the state of an entity to
'Unchanged' or 'Modified' if any entities in the graph have
conflicting key values. This may be because some entities are new and
have not yet received database-generated key values. In this case use
the 'Add' method or the 'Added' entity state to track the graph and
then set the state of non-new entities to 'Unchanged' or 'Modified' as
appropriate.
I have tried the following:
Attaching before setting to EntityState.Modified
Adding AsNoTracking() on querying if the object exists(No exception but DB is not updated) - https://stackoverflow.com/a/23228001/919426
Saving using the base entity _dbContext.Users instead of the Employee entity - https://stackoverflow.com/a/25575634/919426
None of which is working for me now.
What could I have gotten wrong for some of those solutions not to work in my situation?

EF already includes a way to map properties without resorting to Automapper, assuming you do not have navigation properties to update:
public bool UpdateEmployee(Employee employee)
{
var entity = _dbContext.Employees.Where(c => c.Id == employee.Id).AsQueryable().FirstOrDefault();
if (entity == null)
{
_dbContext.Employees.Add(employee);
}
else
{
_dbContext.Entry(entity).CurrentValues.SetValues(employee);
}
return _dbContext.SaveChanges() > 0;
}
This usually generates a better SQL statement since it will only update the properties that have changed.
If you still want to use the original method, you'll get rid of entity from the context, either using AsNoTracking (not sure why it didn't update in your case, it should have no effect, so the problem might be something else) or as modifying your query to prevent it from materializing the entity in the first place, using something like bool exists = dbContext.Employees.Any(c => c.Id == employee.Id) for example.

This worked for myself
var aExists = _db.Model.Find(newOrOldOne.id);
if(aExists==null)
{
_db.Model.Add(newOrOldOne);
}
else
{
_db.Entry(aExists).State = EntityState.Detached;
_db.Entry(newOrOldOne).State = EntityState.Modified;
}

I've encountered the same thing when using a repository and unit of work pattern (as documented in the mvc4 with ef5 tutorial).
The GenericRepository contains an Update(TEntity) method that attempts to Attach then set the Entry.State = Modified. The up-voted 'answer' above doesn't resolve this if you are going to stick to the uow / repo pattern.
I did attempt to use the detach process prior to the attach, but it still failed for the same reason as indicated in the initial question.
The reason for this, it turns out, is that I was checking to see if a record existed, then using automapper to generate an entity object from my dto prior to calling update().
By checking for the existance of that record, i put the entity object in scope, and wasn't able to detach it (which is also the reason the initial questioner wasn't able to detach)... Tt tracked the record and didn't allow any changes after I automapper'ed the dto into an entity and then attempted to update.
Here's the generic repo's implementation of update:
public virtual void Update(TEntity entityToUpdate)
{
dbSet.Attach(entityToUpdate);
context.Entry(entityToUpdate).State = EntityState.Modified;
}
This is my PUT method (i'm using WebApi with Angular)
[HttpPut]
public IHttpActionResult Put(int id, Product product)
{
IHttpActionResult ret;
try
{
// remove pre-check because it locks the record
// var e = unitOfWork.ProductRepository.GetByID(id);
// if (e != null) {
var toSave = _mapper.Map<ProductEntity>(product);
unitOfWork.ProductRepository.Update(toSave);
unitOfWork.Save();
var p = _mapper.Map<Product>(toSave);
ret = Ok(p);
// }
// else
// ret = NotFound();
}
catch (DbEntityValidationException ex)
{
ret = BadRequest(ValidationErrorsToMessages(ex));
}
catch (Exception ex)
{
ret = InternalServerError(ex);
}
return ret;
}
As you can see, i've commented out my check to see if the record exists. I guess i'll see how it works if I attempt to update a record that no longer exists, as i no longer have a NotFound() return opportunity.
So to answer the initial question, i'd say don't look for entity==null before making the attempt, or come up with another methodology. maybe in my case, i could dispose of my UnitOfWork after discovery of the object and then do my update.

You need to detach to avoid duplicate primary key exception whist invoking SaveChanges
db.Entry(entity).State = EntityState.Detached;

Entity Framework entity state is modified without any modification

I have the following issue on update of the entities. Given below is my WCF method. (Update is called by public Save method after determining if it is update or add)
protected bool UpdateSalesMaster(SalesMaster order)
{
using (var context = new MyContext())
{
SalesMaster original = context.SalesMasters.FirstOrDefault(o => o.OrderID == order.OrderID);
if (original != null)
{
context.Entry(original).CurrentValues.SetValues(order);
foreach (SalesDetail detail in order.SalesDetails)
{
if (detail.OrderDetailID == 0)
context.SalesDetails.Add(detail);
else
{
SalesDetails originalDetail = context.SalesDetails.FirstOrDefault(o => o.OrderDetailID == detail.OrderDetailID);
if (originalDetail != null)
context.Entry(originalDetail).CurrentValues.SetValues(detail);
}
}
context.SaveChanges();
return true;
}
else
{
throw new FaultException(string.Format("Invalid Order specified: {0}", order.OrderID));
}
}
}
When I just update the OrderDate in SalesMaster and don't change any in the detail, an update query is fired to the database for detail. I expected to see Update query only for SalesMaster.
Can someone let me know what am I doing wrong here? I don't want to fire update queries to the DB if nothing is changed.
I use the approach of getting the original value from the database to determine if any values are updated using context.Entry(originalDetail).CurrentValues.SetValues(detail);
I also override the SaveChanges to set the LastModified date by checking for IAuditable implementation of the entity. This is when I find that the state of the detail entity is identified as modified. But the only update that happens in the DB is LastModifiedBy which was updated in my save changes. I am not sure how it was set to state of Modified when nothing changed in detail.
public override int SaveChanges()
{
var changeSet = ChangeTracker.Entries<IAuditable>();
if (changeSet != null)
{
foreach (var entry in changeSet.Where(c => c.State != EntityState.Unchanged))
{
if (entry.State == EntityState.Added)
entry.Entity.DateCreated = DateTime.Now;
if (entry.State == EntityState.Modified)
{
entry.Property(a => a.CreatedByUser).IsModified = false;
entry.Property(a => a.DateCreated).IsModified = false;
}
entry.Entity.DateModified = DateTime.Now;
}
}
try
{
return base.SaveChanges();
}
catch (DbEntityValidationException ex)
{
throw ex;
}
}
My solution structure is:
Client - Windows forms UI
Entities - POCO as seperate library
WCF - All business logic, add, update, delete of objects.
Data - Entity Framework context with Fluent mapping.

Depending on how you set up you POCOs, EF will default to one of two ways to check changes on an entity.
If ALL your POCOs properties are virtual, EF will use proxy object that inherit your POCO type, with all the properties overridden to track changes.
I assume that in this circumstance, using SetValues on the whole object WILL trigger the dirty flag, that will cause EF to generate an Update query to the database.
If your are not using proxies, your IAuditable implementation would be the primary suspect as brumScouse suggested.

How to update using Entity Framwork by passing in object

How do I update using Entity Framework? I'm passing in the object with the updated values, but I don't see an Update method.
public void UpdateRecipient(Domain.Entities.RecipientEntity recipient)
{
using (EfDbContext context = CreateEfDbContext(recipient.ApplicationId.ToString()))
{
context.Recipients. //?? I don't see an update method
context.SaveChanges();
}
}

Three steps:
Get the item to update from the context
Copy over the updated properties from the entity you pass your update method
Save the changes.
Roughly:
using (EfDbContext context = CreateEfDbContext(recipient.ApplicationId.ToString()))
{
var toUpdate = context.Recipients.SingleOrDefault(r => r.Id == recipient.Id);
if (toUpdate != null)
{
toUpdate.Field1 = recipient.Field1;
// Map over any other field data here.
context.SaveChanges();
}
else
{
// Handle this case however you see fit. Log an error, throw an error, etc...
}
}

There is another way of updating object without re-fetching it from the database again thus by saving cost of a trip to database. The object being attached must have a value for its primary key.
Attach the updated object to the context
Change it's state to 'modified'.
Call SaveChanges() method of the context
Like:
public void UpdateRecipient(Domain.Entities.RecipientEntity recipient)
{
using (EfDbContext context = CreateEfDbContext(recipient.ApplicationId.ToString()))
{
context.Attach(recipient);
context.ObjectStateManager.ChangeObjectState(recipient,EntityState.Modified);
context.SaveChanges();
}
}

If you're updating the record then you'd do something like this:
//Retrieve the entity to be updated
Entity row = context.Recipients.Single(a => a.Id == recipient.Id);
//Update a column
row.Name = recipient.Name;
//Save changes
context.SaveChanges();
If you want to update/add things at the same time then you'd do:
if(!context.Recipients.Any(a => Id == recipient.Id))
{
context.Recipients.Add(recipient);
}
else
{
Entity row = context.Recipients.Single(a => a.Id == recipient.Id);
row.Name = recipient.Name;
}
context.SaveChanges();