During the execution of the following piece of code, I get the message
Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.
And there are loads of occurrences of that in here, but I didn't find a solution to my problem.
This only happens to me because I'm running _db.SaveChanges() two times inside one transaction (_db is my database context object), and I HAVE to do so because I need the generated ID that it gives me in order to proceed with the code.
If anyone can help me, I'd appreciate it. Also, if you know a way to proceed without the two _db.SaveChanges() or with a different way of approaching the transaction, I welcome you to show it.
using (var trans = _db.Database.BeginTransaction())
{
try
{
var f = cbxFornecedor.SelectedItem as Fornecedor;
var c = new Compra
{
CompraId = compra.CompraId,
DataCompra = dtpDataCompra.Value,
ListaProdutos = new List<ListaProdutos>(),
Fornecedor = f,
Referencia = tbxReferencia.Text,
Situacao = rbtEntregue.Checked
};
_db.Compras.Add(c);
_db.SaveChanges();
foreach (var cada in _itens)
c.ListaProdutos.Add(new ListaProdutos
{
Compra = c,
CompraId = c.CompraId,
Produto = cada.ProdutoClasse,
ProdutoId = cada.ProdutoClasse.ProdutoId,
Valor = cada.ValorTotal,
Quantidade = cada.Quantidade,
});
foreach (var cada in c.ListaProdutos)
if (_db.ListaProdutos.Find(cada.CompraId, cada.ProdutoId) != null)
_db.Entry(cada).State = EntityState.Modified;
else
_db.ListaProdutos.Add(cada);
_db.Entry(c).State = EntityState.Modified;
_db.SaveChanges();
trans.Commit();
}
catch (Exception ex)
{
trans.Rollback();
MessageBox.Show(this, ex.Message, #"Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
And, just to be clear, I know that my problem is with that fact that the transaction is there. I tried removing it and it worked. Also, if I take out the second _db.SaveChanges(), it works too.
The exception is only thrown in the second _db.SaveChanges(), and only if it is surrounded by the transaction block.
It is not direct answer to your question, but it may be helpful.
You do not need to specify Compra and CompraId for new ListaProdutos because EF smart enough to figure it out. Also it looks like that you do not need _db.ListaProdutos.Find(cada.CompraId, cada.ProdutoId) != null check because cada.CompraId - is new Id and it can not be in DB at this moment. Also you do not need _db.ListaProdutos.Add(cada); because EF already new that you are adding this records. Can you try next code?
var f = cbxFornecedor.SelectedItem as Fornecedor;
var c = new Compra
{
DataCompra = dtpDataCompra.Value,
ListaProdutos = new List<ListaProdutos>(),
Fornecedor = f,
Referencia = tbxReferencia.Text,
Situacao = rbtEntregue.Checked
};
_db.Compras.Add(c);
foreach (var cada in _itens)
c.ListaProdutos.Add(new ListaProdutos
{
Produto = cada.ProdutoClasse,
ProdutoId = cada.ProdutoClasse.ProdutoId,
Valor = cada.ValorTotal,
Quantidade = cada.Quantidade,
});
_db.SaveChanges();
Related
I want to log new and modified records. This code works just fine for Modified Records.
But with Added records, there is an issue. Since it is new to the Database, there is not yet a primary key for it. So there is no way to log which record was added.
However, if I try to log the records after the save, the EntityState is no longer Added. So I don't know what was added.
The only solution I have been able to come up with is to save a list of the new records, and then after the save, then Log the changes. But that seems like a workaround.
Is there some way to resolve this?
private List<Event> LogChanges(EntityEntry entityEntry, Enums.TableNames tableName)
{
List<Event> result = new List<Event>();
var databaseValues = entityEntry.GetDatabaseValues();
foreach (var property in entityEntry.CurrentValues.Properties.Where(a=> a.Name !="TenantId"))
{
string original = databaseValues[property]?.ToString();
string current = entityEntry.CurrentValues[property]?.ToString();
if(!object.Equals(original,current))
{
result.Add(
new Event()
{
AppUserId = this._appUserProvider.CurrentAppUserId,
EventDate = DateTimeOffset.UtcNow,
EventTypeId = (int)Enums.EventTypes.Modified,
TenantId = databaseValues.GetValue<int>("TenantId"),
RecordId = databaseValues.GetValue<int>("Id"),
ColumnName = property.Name,
OriginalValue = original,
NewValue = current,
TableId = (int)tableName
});
}
}
return result;
}
This library adds triggers to EntityFrameworkCore. Using the Triggers it provides is a much cleaner way to accomplish the above.
I'm having to write a app that effectively copies data from one databaseA.table to databaseB.table but there are a few fields in databaseB that aren't in databaseA.
I've come up with basic code below. The insert works and the update doesn't trow an error, however, the update doesn't actually update any records.
I've confirmed that the bcEmployee object in the update has the new values from databaseA like it should. The employee object is the record from databaseA.
Am I missing something to make this update?
BC_employee bcEmployee = new BC_employee();
bcEmployee.emp_id = employee.emp_id;
bcEmployee.emp_firstname = employee.emp_firstname;
bcEmployee.emp_lastname = employee.emp_lastname;
using (BCcontext ctx = new BCcontext())
{
var existBCemployee = ctx.employee.Find(employee.emp_id);
if (existBCemployee == null) //Insert
{
//Set default values that aren't in the original database
bcEmployee.emp_paystat = null;
bcEmployee.password = null;
bcEmployee.enroll_date = null;
ctx.employee.Add(bcEmployee);
}
else
{
ctx.Entry(existBCemployee).CurrentValues.SetValues(bcEmployee);
}
ctx.SaveChanges();
}
If I have a main table, lets say orders, and a sub table of items and the items table has a fields for item number BUT it also has a nullable (optional) field for color that applied only to certain items. How would I update the items table, at the same time as the orders table, using Entity Framework?
Here is a code example of what I have so far. Two problems, I'm only entering one of my items and, from what my research indicates, I can't add another field to the items table?
foreach (Guid c in AllItems)
{ Items.OrderItemID = Guid.NewGuid();
ITemsOrderID = order.OrderID;
ITems.ItemID = c;
If (ItemID = ItemThatLetsYouChoseAColorID)
{
Items.ItemColorID = ColorID;
} else {
Items.ItemColorID = null;
}
}
context.Orders.AddObject(Orders);
context.Items.AddObject(Items);
context.SaveChanges();
My Orders table gets a record inserted, and the Items gets ONE record inserted. I'm missing something basic here, I'm afraid. BTW, this is Entity Framework 4.0, which. I believe, does not require the use of EntityKey.
You're adding an object to the Items collection only one time after the scope of your foreach.
Have you tested something like:
foreach (Guid c in AllItems)
{
var Item = new Item();
Item.OrderItemID = Guid.NewGuid();
Item.OrderID = order.OrderID;
Item.ItemID = c;
If (ItemID = ItemThatLetsYouChoseAColorID)
{
Item.ItemColorID = ColorID;
}
else
{
Item.ItemColorID = null;
}
context.Items.AddObject(Items);
}
context.Orders.AddObject(order);
context.SaveChanges();
And I'm not sure to understand what you mean by
I can't add another field to the items table
You should be more precise about what you actually expect. Insert a row, add a column in the table...? What is a "field"?
Here is the working code. I had the new Item outside the foreach item loop, so was overwriting the value. Also, I need to add each one to the context. I had a hard time with this, hope it helps someone else:
<-fill the order object->
foreach (Guid i in Items)
{
**Items item = new Items();**
item.ItemID = Guid.NewGuid();
item.OrderID = order.OrderID;
if (i == ItemWithColorGuid)
{
foreach (Guid c in Colors)
{
**Items color = new Items();**
color.ItemsID = Guid.NewGuid();
color.OrderID = order.orderID;
color.itemID = g;
color.colorID = c;
context.item.AddObject(color);
}
}
else
{
item.ItemID = i;
item.ColorID = null;
context.item.AddObject(item);
}
}
context.orders.AddObject(order);
context.SaveChanges();
I am having a real issue with the EF v1. I have quite a big EDMX with maybe 50 entities mapped, but this one entity is causing me grief.
The entity has mappings to other entities which in effect are reference tables, but for some reason it is trying to do an insert and not just update itself.
Here is a fragment of my code:
using (var context = new someEntities()) {
var studentCourseJoin =
context.StudentCourseJoinSet.Where(o => o.Code == scjCode).First();
studentCourseJoin.EntryStatus = new EntryStatus { Code = viewModel.StudentDetails.EntryStatusCode };
studentCourseJoin.ParentalInHigherEducation = new ParentalInHigherEducation { Code = viewModel.StudentDetails.ParentalInHigherEducationCode };
studentCourseJoin.School = new School { Code = viewModel.StudentDetails.SchoolCode };
studentCourseJoin.Institution = new Institution { Code = viewModel.StudentDetails.InstitutionCode };
studentCourseJoin.LastSchoolEndYear = viewModel.StudentDetails.LastSchoolEndYear;
studentCourseJoin.LastInstitutionEndYear = viewModel.StudentDetails.LastInstitutionEndYear;
// Blows up here trying to do an insert on the studentCourseJoin.Institution.
// But if I removed this one, then it will blow up on another one.
context.SaveChanges(true);
}
If anyone has ANY ideas please, they would help a lot.
Try adding those lines before calling SaveChanges:
ObjectStateEntry entry = context.ObjectStateManager.GetObjectStateEntry(studentCourseJoin);
entry.ChangeState(EntityState.Modified);
Update:
Try this for Institution instead:
studentCourseJoin.Institution = context.Institutions.FirstOrDefault(i => i.Code == viewModel.StudentDetails.InstitutionCode);
I'm new to the entity framework and I'm really confused about how savechanges works. There's probably a lot of code in my example which could be improved, but here's the problem I'm having.
The user enters a bunch of picks. I make sure the user hasn't already entered those picks.
Then I add the picks to the database.
var db = new myModel()
var predictionArray = ticker.Substring(1).Split(','); // Get rid of the initial comma.
var user = Membership.GetUser();
var userId = Convert.ToInt32(user.ProviderUserKey);
// Get the member with all his predictions for today.
var memberQuery = (from member in db.Members
where member.user_id == userId
select new
{
member,
predictions = from p in member.Predictions
where p.start_date == null
select p
}).First();
// Load all the company ids.
foreach (var prediction in memberQuery.predictions)
{
prediction.CompanyReference.Load();
}
var picks = from prediction in predictionArray
let data = prediction.Split(':')
let companyTicker = data[0]
where !(from i in memberQuery.predictions
select i.Company.ticker).Contains(companyTicker)
select new Prediction
{
Member = memberQuery.member,
Company = db.Companies.Where(c => c.ticker == companyTicker).First(),
is_up = data[1] == "up", // This turns up and down into true and false.
};
// Save the records to the database.
// HERE'S THE PART I DON'T UNDERSTAND.
// This saves the records, even though I don't have db.AddToPredictions(pick)
foreach (var pick in picks)
{
db.SaveChanges();
}
// This does not save records when the db.SaveChanges outside of a loop of picks.
db.SaveChanges();
foreach (var pick in picks)
{
}
// This saves records, but it will insert all the picks exactly once no matter how many picks you have.
//The fact you're skipping a pick makes no difference in what gets inserted.
var counter = 1;
foreach (var pick in picks)
{
if (counter == 2)
{
db.SaveChanges();
}
counter++;
}
I've tested and the SaveChanges doesn't even have to be in the loop.
The below code works, too.
foreach (var pick in picks)
{
break;
}
db.SaveChanges()
There's obviously something going on with the context I don't understand. I'm guessing I've somehow loaded my new picks as pending changes, but even if that's true I don't understand I have to loop over them to save changes.
Can someone explain this to me?
Here's updated working code based on Craig's responses:
1) Remove the Type then loop over the results and populate new objects.
var picks = (from prediction in predictionArray
let data = prediction.Split(':')
let companyTicker = data[0]
where !(from i in memberQuery.predictions
select i.Company.ticker).Contains(companyTicker)
select new //NO TYPE HERE
{
Member = memberQuery.member,
Company = db.Companies.Where(c => c.ticker == companyTicker).First(),
is_up = data[1] == "up", // This turns up and down into true and false.
}).ToList();
foreach (var prediction in picks)
{
if (includePrediction)
{
var p = new Prediction{
Member = prediction.Member,
Company = prediction.Company,
is_up = prediction.is_up
};
db.AddToPredictions(p);
}
}
2) Or if I don't want the predictions to be saved, I can detach the predictions.
foreach (var prediction in picks) {
if (excludePrediction)
{
db.Detach(prediction)
}
}
The reason is here:
select new Prediction
{
Member = memberQuery.member,
These lines will (once the IEnumerable is iterated; LINQ is lazy) :
Instantiate a new Prediction
Associate that Prediction with an existing Member, *which is attached to db.
Associating an instance of an entity with an attached entity automatically adds that entity to the context of the associated, attached entity.
So as soon as you start iterating over predictionArray, the code above executes and you have a new entity in your context.