I am new to MVC. I am getting error while updating multiple records to database using EF.
I want to create a group and add members in it.
I created to list
boxes. I have loaded all members in left box.
First time, I created the Group and added members from first box to second box, and saved
the form. All data saved successfully.
While I come to edit the group, I want to add/remove some members from the group, I got
error.
I used the following code for edit mode.
if (!string.IsNullOrEmpty(groupView.GroupName) && groupView.MemberIDs.Count > 0)
{
Groups group = new Groups();
List<GroupMembers> existingMembers = null;
if (groupView.GroupID > 0)
{
group.GroupID = groupView.GroupID;
//db.Entry(group).State = EntityState.Modified;
existingMembers = db.GroupMembers.ToList();
}
else
{
group.GroupID = groupView.GroupID;
group.GroupName = groupView.GroupName;
group.IsActive = true;
db.Groups.Add(group);
}
GroupMembers groupMembers, member;
foreach (short memberId in groupView.MemberIDs)
{
groupMembers = new GroupMembers();
if (groupView.GroupID > 0)
{
//Check whether the Member already exists in the group
member = existingMembers.Where(gm => gm.GroupID == groupView.GroupID && gm.MemberID == memberId).FirstOrDefault();
if (member != null)
{
groupMembers.GroupMemberID = member.GroupMemberID;
db.Entry(groupMembers).State = EntityState.Modified;
}
else
groupMembers.GroupMemberID = 0;
}
groupMembers.GroupID = group.GroupID;
groupMembers.MemberID = memberId;
groupMembers.IsActive = Convert.ToBoolean(groupView.IsActive);
if (groupMembers.GroupMemberID == 0)
db.GroupMembers.Add(groupMembers);
}
db.SaveChanges();
At runtime I received the following exception:
An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key
If I removed the following code from the above coding, duplicate data inserted in DB.
db.Entry(group).State = EntityState.Modified;
I am new to MVC, EF, as per my knowledge I wrote the above coding. I searched and checked some questions with the error information, but I am not able to understand clearly. So I put my coding. Please guide me to resolve this issue.
Thanks in advance.
Related
I have a simple association table whose PK isn't referenced anywhere but when I am trying to delete a record from it in the following way, I get an error. I am using EF code-first. Any help would be very very helpful. Thanks in advance.
List<ViolationTypeNOV> novRels = UnitOfWork.Context.ViolationTypeNOVs.Where(x => x.NOVId == nov.NOVId).Include("ViolationType").Include("NOV").ToList();
foreach (ViolationTypeNOV o in novRels)
{
UnitOfWork.Context.ViolationTypeNOVs.Remove(o);
}
UnitOfWork.Context.SaveChanges();
Here is the error message I am getting. If the table's PK isn't referenced in any way, why is it failing with this error? Just not able to understand:
The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted.
The same thing if I am running through SSMS same thing is working though:
DELETE ViolationTypeNOVs
WHERE ViolationTypeNOVId = 2
Why?
But again if I am running the same query through context as below, I get the same error at the calling SaveChanges:
foreach (ViolationTypeNOV o in novRels)
{
string str = string.Format("Delete ViolationTypeNOVs where ViolationTypeNOVId = {0}", new object[] { o.ViolationTypeNOVId });
UnitOfWork.Context.Database.ExecuteSqlCommand(str);
}
UnitOfWork.Context.SaveChanges();
It seems like some of the objects within the context aren't nulling or getting deleted, is there anyway to clear them all in one go? Because these ids/objects are used in multiple places in the code - please let me know how to clear them all - thanks a lot.
Any help please?
Fixed it - the problem is we need to clear up all the objects and its links that the parent object is using then only we can save the changes thanks here is my solution
public bool Delete(NOV nov, bool performCommit = true)
{
System.Data.Entity.DbContextTransaction dbOperation = null;
if (performCommit)
dbOperation = UnitOfWork.BeginTransaction();
try
{
//-- Remove the Items - "foreach" approach was a problem
// http://weblogs.asp.net/ricardoperes/entity-framework-pitfalls-deleting-orphans
//------------------------------------------------------
// Remove the Violations that are in this NOV
//------------------------------------------------------
List<Violation> violationIdlist = new List<Violation>();
foreach (var v in nov.ViolationNOVs)
{
var a = UnitOfWork.ViolationRepository.GetAll().Where(z => z.ViolationId == v.ViolationId).FirstOrDefault();
violationIdlist.Add(a);
}
foreach (var v in violationIdlist)
{
var a = nov.ViolationNOVs.Where(x => x.NOVId == nov.NOVId && x.ViolationId == v.ViolationId)?.FirstOrDefault();
nov.ViolationNOVs.Remove(a);
}
nov.IssuedBy.Clear();
//deleting all OneToMany references to NOV
List<ViolationTypeNOV> novRels = UnitOfWork.Context.ViolationTypeNOVs.Where(x => x.NOVId == nov.NOVId).Include("ViolationType").Include("NOV").ToList();
nov?.ViolationTypeNOVs?.Clear();
//foreach (ViolationTypeNOV o in novRels)
//{
// UnitOfWork.Context.ViolationTypeNOVs.Remove(o);
// o?.ViolationType?.ViolationTypeNOVs?.Remove(o);
// nov?.ViolationTypeNOVs?.Remove(o);
//}
UnitOfWork.Context.ViolationTypeNOVs.RemoveRange(novRels);
List<ViolationNOV> violationNOVs = UnitOfWork.Context.ViolationNOVs.Where(x => x.NOVId == nov.NOVId).Include("Violation").Include("NOV").ToList();
nov?.ViolationNOVs?.Clear();
UnitOfWork.Context.ViolationNOVs.RemoveRange(violationNOVs);
List<CaseNOV> caseNOVs = UnitOfWork.Context.CaseNOVs.Where(x => x.NOVId == nov.NOVId).Include("Case").Include("NOV").ToList();
nov?.CaseNOVs?.Clear();
UnitOfWork.Context.CaseNOVs.RemoveRange(caseNOVs);
UnitOfWork.Context.SaveChanges();
if (dbOperation != null)
dbOperation.Commit();
LogHandler.LogInfo(2521, "Deleted NOV " + nov.NOVNumber);
return true;
}
catch (Exception ex)
{
LogHandler.LogError(2523, "Commit Fail in NOV Delete", ex);
if (dbOperation != null)
dbOperation.Rollback();
throw ex;
}
}
This statement has fixed the problem: UnitOfWork.Context.ViolationTypeNOVs.RemoveRange(novRels); thanks a lot for everybody who tried to help me
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();
}
I am having an issue understanding why when adding a new entity to a DbSet of ObjectContext, that entity is not found will looking it up again.
using (var db = new SmartrailDB())
{
var cart01 = db.Carts.SingleOrDefault(x => x.Number == 0);
if (cart01 == null)
{
cart01 = new Cart { Number = 0 };
db.Carts.Add(cart01);
}
var cart02 = db.Carts.SingleOrDefault(x => x.Number == 0); // Should find the cart I just added - right?
Assert.IsNotNull(cart02); // Fails because cart02 does not exist in the db.Carts collection
}
Is anyone able to tell me what I am doing wrong here?
Also late on a Friday here so brain half asleep now.
You have to update your context before you try to access the entity. Just do:
db.SaveChanges(); right after db.Cart.Add(cart01);
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.