I'm trying to update a POCO object using entity framework in the following way:
context.Jobs.Attach(job);
context.SaveChanges();
That does not work. No error is thrown, it just isn't updating the values in the database.
I tried:
context.Jobs.AttachTo("Jobs", job);
context.SaveChanges();
Nothing wrongs, still no error and no updates.
What about changing the ObjectState?
context.ObjectStateManager.ChangeObjectState(job, System.Data.EntityState.Modified);
From MSDN: ObjectStateManager.ChangeObjectState Method.
I guess you are working with detached object - check second part of this answer.
another reason that this may not work is when the corresponding Jobs.cs file has been committed but the .edmx file has not. This means that the property is present but not mapped and therefore EF does not consider the object modified. For example:
...
using (var dao = new DbContext())
{
dao.Jobs.Attach(job);
job.SomeProperty = 1234; // SomeProperty exists but is not in the .edmx
dao.SaveChanges();
}
if SomeProperty is present in Jobs.cs but missing from the .edmx file, this code will compile and execute without a hint that anything is wrong but SomeProperty will not be updated in the Database. Took me the best part of a day to find this one.
you have to get the job first then you could successfully update it, chk below snippet
var job = context.Jobs.Where(p => p.Id == id).FirstOrDefault();
//apply your changes
job.Title = "XXXX";
///....
context.SaveChanges();
My issue was that I was attaching after I updated the object, when in-fact, you have to attach BEFORE you update any properties
context.Table.Attach(object);
object.MyProperty = "new value";
context.Table.SaveChanges();
Related
I have a weird problem with Entity Framework code first migrations. I've been using EF and code first migrations on a project for months now and things are working fine. I recently created a new migration and when running Update-Database a restored backup of my database I get this error:
The model backing the context has changed since the database was
created. Consider using Code First Migrations to update the database
The migration does something like the following:
public override void Up()
{
using (SomeDbContext ctx = new SomeDbContext())
{
//loop through table and update rows
foreach (SomeTable table in ctx.SomeTables)
table.SomeField = DoSomeCalculation(table.SomeField);
ctx.SaveChanges();
}
}
I'm not using the Sql() function because DoSomeCalculation must be done in C# code.
Usually when I get something like this is means that I have updated my model somehow and forgot to create a migration. However that's not the case this time. The weird thing is that the error isn't even occurring on a migration that I created a few days ago and had been working fine.
I looked a quite a few articles about this and they all seems to say call
Database.SetInitializer<MyContext>(null);
Doing that does seem to work, but my understanding (based on this article) is that doing that will remove EF's ability to determine when the database and model are out of sync. I don't want to do that. I just want to know why it thinks they are out of sync all of a sudden.
I also tried running Add-Migration just to see if what it thought changed about the model but it won't let me do that stating that I have pending migrations to run. Nice catch 22, Microsoft.
Any guesses as to what's going on here?
I'm wondering if maybe the fact that migration listed above is using EntityFramework is the problem. Seems like maybe since it's not the latest migration anymore, when EF gets to it tries to create a SomeDbContext object it checks the database (which is not fully up to date yet since we're in the middle of running migrations) against my current code model and then throws the "context has changed" error.
It's possibly related to your using EF within the migration. I'm not sure how you're actually managing this, unless you've set a null database initialiser.
If you need to update data within a migration, use the Sql function, e.g.
Sql("UPDATE SomeTable SET SomeField = 'Blah'");
You should note that the Up() method is not actually running at the time of doing the migration, it's simply used to set up the migration which is then run later. So although you may think you've done something in the migration above the bit where you're using EF, in reality that won't have actually run yet.
If you cannot refactor your calculation code so it can be written in SQL, then you would need to use some mechanism other than migrations to run this change. One possibility would be to use the Seed method in your configuration, but you would need to be aware that this does not keep track of whether the change has been run or not. For example...
internal sealed class Configuration : DbMigrationsConfiguration<MyContext>
{
public Configuration()
{
AutomaticMigrationsEnabled = false;
}
protected override void Seed(MyContext context)
{
// Code here runs any time ANY migration is performed...
}
}
I tried replacing the EntityFramework code with regular ADO.NET code and it seems to work. Here is what it looks like:
public override void Up()
{
Dictionary<long, string> idToNewVal = new Dictionary<long, string>();
using (SqlConnection conn = new SqlConnection("..."))
{
conn.Open();
using (SqlCommand cmd = new SqlCommand("SELECT SomeID, SomeField FROM SomeTable", conn))
{
SqlDataReader reader = cmd.ExecuteReader();
//loop through all fields, calculating the new value and storing it with the row ID
while (reader.Read())
{
long id = Convert.ToInt64(reader["SomeID"]);
string initialValue = Convert.ToString(reader["SomeField"]);
idToNewVal[id] = DoSomeCalculation(initialValue);
}
}
}
//update each row with the new value
foreach (long id in idToNewVal.Keys)
{
string newVal = idToNewVal[id];
Sql(string.Format("UPDATE SomeTable SET SomeField = '{0}' WHERE SomeID = {1}", newVal, id));
}
}
I have the following scenario:
I am using EF with Repository pattern and Unit Of Work from here
Then I extended my partial class and have created a Finder class which have GetAll and other methods.
You can this see below:
Below you can see that I am using a unit of work class with repositories of all classes to get the instance from the generic repository:
protected Repository<Category> _CategoryRepository;
public Repository<Category> CategoryRepository
{
get { return _CategoryRepository ?? (_CategoryRepository = new Repository<Category>(context)); }
}
So in this way I had different repositories and when getting an entity from db and updating it from a different context caused problems. So I used this method to use for context lifetime management. And it resolved that issue.
Now the problem I am facing is in the following code:
var cat = Instance.Category.GetSingle(c => c.CategoryID == 7);
var orignal = cat.CategoryName;
var expected = cat.CategoryName + " Test Catg Update";
cat.CategoryName = expected;
cat.Update(); //This doesn't actually update due to a validation in place (which is correct)
cat = Instance.Category.GetSingle(c => c.CategoryID == 7);
Assert.AreEqual(cat.CategoryName, expected);
When I use Update and I have some validators in it, and the Update fails (for example due to size of the string exceeds 15 characters). When I try to call GetSingle (2nd last line of above code) again, it brings me the same old record which is [cat.CategoryName + " Test Catg Update"]. Is this a normal way? If not how can this be fixed so I can reload the object from database.
Let me know if you need any other code or reference.
in your Update() method, if the validation fails, simply set the state of the entity to EntityState.Unchanged. Under the covers, changing the state of an entity from Modified to Unchanged first sets the values of all properties to the original values that were read from the database when it was queried, and then marks the entity as Unchanged. This will also reject changes to FK relationships since the original value of the FK will be restored.
You may be able to take advantage of the ObjectContext.Refresh() method to handle this as well. However, this is on the ObjectContext, so you would need a method to handle it in your UoW. The refresh method would be something like context.Refresh(RefreshMode.ServerWins, entity);
I am working with a database first model in Entity Framework 5 and when I attempt to add a row, I get the following error:
"No views were found in assemblies or could be generated for Table 'ui_renewals'."
The table exists in my EDMX and the template generated a ui_renewals class. I've deleted the table from the EDMX and added it again using the Update Model from Database option and I get the same error. Creating a separate connection for it resolves the issue, but that seems like a less-than-ideal solution (more like a kludge) not to mention it makes it more difficult to maintain in the future.
Any ideas on how to fix this so that I can add or update (I've tried both) a row in ui_renewals?
Here is the code I'm currently using - only difference before was using db as a DBContext instead of ui (yes, receipt is misspelled - gotta love legacy stuff)
[HttpPost]
public bool UpdateTeacher(string login_id, string password, UIRenewal data)
{
if (ModelState.IsValid)
{
// map from UIRenewal VM to ui_renewal
ui_renewals Renewal = Mapper.Map<UIRenewal, ui_renewals>(data);
// check to see if this is a new entry or not
var tmp = ui.ui_renewals.Find(Renewal.reciept);
if (tmp == null)
ui.ui_renewals.Add(Renewal);
else
{
// mark as modified
db.Entry(Renewal).State = EntityState.Modified;
}
// save it
try
{
ui.SaveChanges();
}
catch (DBConcurrencyException)
{
return false;
}
return true;
}
return false;
}
I should mention that I do have a view in the model (v_recent_license).
I know this is a very old question, however as I haven't found any other topics like this, I'll post my answer.
I have had the same Exception thrown. I found that, in a failed attempt to optimize EF performance, following the advices found here, I left behind this piece of code in EF .edmx code-behind:
<EntityContainerMapping StorageEntityContainer="XXXModelStoreContainer" CdmEntityContainer="YYYEntities" GenerateUpdateViews="false">
I removed the GenerateUpdateViews="false" string, and all is working again.
(The Exception message is a little misleading in my opinion).
I have following code to add or update the Entity object. finding the object by primary key, based on the response I am adding or updating the object.
Adding record works, but during update its giving this error message "An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key"
In my MSSQL database I have only one record.
var v = db.Envelopes.Find(model.ReportDate, model.Service);
if (v == null)
{
db.Envelopes.Add(model);
db.SaveChanges();
ViewBag.status = "Record Add successfully";
ModelState.Clear();
}
else
{
db.Entry(model).State = EntityState.Modified;
db.SaveChanges();
}
How can I fix this error message?
As mentioned by #anon you can't attach model once you loaded the entity with the same key. The changes must be applied to attached entity. Instead of this:
db.Entry(model).State = EntityState.Modified;
use this:
db.Entry(v).CurrentValues.SetValues(model);
If an earlier query read the entity to be updated and that's why you're getting the error, you can change that query to AsNoTracking. See the AsNoTracking example in:
http://www.asp.net/entity-framework/tutorials/advanced-entity-framework-scenarios-for-an-mvc-web-application
I assume you are saying that your error occurs here:
db.Entry(model).State = EntityState.Modified;
Once you execute Find(), your Envelope is already being tracked by your context. This means that if you need to change a property, just change it on v, and then call SaveChanges(). Don't worry about setting the state to Modified.
If you set your context to AsNoTracking() this will stop aspmvc tracking the changes to the entity in memory (which is what you want anyway on the web). Don't forget the using statement.
using System.Data.Entity;
db.Envelopes.AsNoTracking().Find(model.ReportDate, model.Service);
I got this from this forum post ->
http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/advanced-entity-framework-scenarios-for-an-mvc-web-application
I'm using this because I have already created a new instance, and populated the properties I need to update.
var key=this.CreateEntityKey("Envelopes",model);
ObjectStateEntry ose;
if(this.ObjectStateManager.TryGetObjectStateEntry(key, out ose)){
var entity=(Page)ose.Entity;
Envelopes.Detach(entity);
}
this.Envelopes.Attach(model);
And another approach to solve the issue is detaching tracked entity and re-attaching the modified one. See my solution here.
To facilitate control reuse we created a solution with three separate projects: a control library, Silverlight client, and ASP.NET backend. The control library has no reference to the RIA Services-generated data model classes so when it needs to interact with it, we use reflection.
This has worked fine so far but I've hit a bump. I have a DataGrid control where the user can select a row, press the 'delete' button, and it should remove the entity from the collection. In the DataGrid class I have the following method:
private void RemoveEntity(Entity entity)
{
// Use reflection to remove the item from the collection
Type sourceType = typeof(System.Windows.Ria.EntityCollection<>);
Type genericType = sourceType.MakeGenericType(entity.GetType());
System.Reflection.MethodInfo removeMethod = genericType.GetMethod("Remove");
removeMethod.Invoke(this._dataGrid.ItemsSource, new object[] { entity });
// Equivalent to: ('Foo' derives from Entity)
// EntityCollection<Foo> ec;
// ec.Remove(entity);
}
This works on the client side but on the domain service the following error gets generated during the Submit() method:
"The UPDATE statement conflicted with
the FOREIGN KEY constraint
"********". The conflict occurred in
database "********", table "********",
column '********'. The statement has
been terminated."
One thing I noticed is the UpdateFoo() service method is being called instead of the DeleteFoo() method on the domain service. Further inspection shows the entity is going into the ModifiedEntities ChangeSet instead of the RemovedEntities ChangeSet. I don't know if that's the problem but it doesn't seem right.
Any help would be appreciated, thanks,
UPDATE
I've determined that the problem is definitely coming from the reflection call to the EntityCollection.Remove() method. For some reason calling it causes the entity's EntityState property to change to EntityState.Modified instead of EntityState.Deleted as it should.
Even if I try to remove from the collection by completely circumventing the DataGrid I get the exact same issue:
Entity selectedEntity = this.DataContext.GetType().GetProperty("SelectedEntity").GetValue(this.DataContext, null) as Entity;
object foo = selectedEntity.GetType().GetProperty("Foo").GetValue(selectedEntity, null);
foo.GetType().InvokeMember("Remove", BindingFlags.InvokeMethod, null, foo, new object[] { entity });
As a test, I tried modifying the UpdateFoo() domain service method to implement a delete and it worked successfully to delete the entity. This indicates that the RIA service call is working correctly, it's just calling the wrong method (Update instead of Delete.)
public void UpdateFoo(Foo currentFoo)
{
// Original update implementation
//if ((currentFoo.EntityState == EntityState.Detached))
// this.ObjectContext.AttachAsModified(currentFoo, this.ChangeSet.GetOriginal(currentFoo));
// Delete implementation substituted in
Foo foo = this.ChangeSet.GetOriginal(currentFoo);
if ((foo.EntityState == EntityState.Detached))
this.ObjectContext.Attach(foo);
this.ObjectContext.DeleteObject(foo);
}
I've been researching a similar issue.
I believe the issue is you are calling remove with a reference for an EntityCollections within the DomainContext as the root reference rather than using the DomainContext itself as the root.
So...
ParentEntityCollection.EntityCollectionForTEntity.Remove(TEntity);
Produces the EntityState.Modified instead of EntityState.Deleted
Try instead...
DomainContext.EntityCollectionForTEntity.Remove(TEntity);
I think this will produce the result you are seeking.
Hope this helps.
What is the "column" in the "FOREIGN KEY constraint" error? Is this a field in the grid row and collection that coorosponds to that column? Is it possible that the entity you are trying to remove is a column in the row rather than the row itself which is causing an update to the row (to null the column) rather than to delete the row?
I read your update and looks like you've determined that the problem is the reflection.
Have you tried to take the reflection out of the picture?
As in:
private void RemoveEntity(Entity entity)
{
// Use reflection to remove the item from the collection
Type sourceType = typeof(System.Windows.Ria.EntityCollection<>);
Type genericType = sourceType.MakeGenericType(entity.GetType());
// Make sure we have the right type
// and let the framework take care of the proper invoke routine
if (genericType.IsAssignableFrom(this._dataGrid.ItemsSource.GetType()))
((Object) this._dataGrid.ItemsSource).Remove(entity);
}
Yes, I know it's ugly, but some times...
Edited to add
I've updated the code to remove the is keyword.
Now about using the object to make the call to the Remove method, I believe it might work due the late binding of it.