I try to insert "Person" to Database after initialization but I get this problem:
An exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll but was not handled in user code
Additional information: Saving or accepting changes failed because more than one entity of type 'MyProject.Entities.Models.Person' have the same primary key value. Ensure that explicitly set primary key values are unique. Ensure that database-generated primary keys are configured correctly in the database and in the Entity Framework model. Use the Entity Designer for Database First/Model First configuration. Use the 'HasDatabaseGeneratedOption" fluent API or 'DatabaseGeneratedAttribute' for Code First configuration.
in this line :
private void SyncObjectsStatePreCommit()
{
foreach (var dbEntityEntry in ChangeTracker.Entries())
{
dbEntityEntry.State = StateHelper.ConvertState(((IObjectState)dbEntityEntry.Entity).ObjectState);
}
}
How can I deal please with this problem
thanks
Related
Server - IBM WAS 8.5
Open JPA 2.2.3
I am trying to perform a container managed persistence using entity manager.
I have the following three entities defined
Entity MainEntity
Has an id of the type MainEntityPK
MainEntityPK - has the SubEntity1Code from SubEntity1 table and SubEntity2Code from SubEntity2 Table.
Entity SubEntity1 - SubEntity1Code - primary Key
Entity SubEntity2 - SubEntity2Code - primary Key
I try to create an entity of MainEntity which has an existing SubEntity1 and SubEntity2 entries
I first find the entities of SubEntity1 and Seg using
SubEntity1 SubEntity1 =
Entitymanager.find(SubEntity1.class,SubEntity1Code)
SubEntity2 subEntity2 =
Entitymanager.find(SubEntity2.class,SubEntity2Code)
The fetch are successful and I have both the instances of subEntity1 and subEntity2
Now I try to set the Primary Key MainEntityPK as follows
MainEntityPK MainEntityPK = new
MainEntityPK(SubEntity1Code,SubEntity2Code);
MainEntity MainEntity = new MainEntity();
MainEntity.setId(MainEntityPK);
I am getting following error :
Caused by: <openjpa-2.2.3-SNAPSHOT-r422266:1802534 nonfatal user error> org.apache.openjpa.persistence.ArgumentException
: Field: “model.MainEntity.id” of “model.MainEntity#e8df5623” can not be set to “model.MainEntityPK#1768a2” value.
I tried removing the setId call and was getting error as follows:
Caused by: <openjpa-2.2.3-SNAPSHOT-r422266:1802534 nonfatal user error> org.apache.openjpa.persistence.ArgumentException
: Field: “model.MainEntity.id” od “model.MainEntity#e8df5623” can not be set to null value.
Can some one help me in identifying what is wrong in setting the instance of MainEntityPK to id attribute of MainEntity
I'm using Entity Framework to handle data transactions and we have a user entity which had a primary key type integer named ID.
In our SQL Server the Identity specification was set to Yes, Is Identity also set to yes with an auto increment of 1.
To delete a user, I used this code:
ctx.Users.Attach(user);
ctx.Entry(user).State = EntityState.Deleted;
ctx.SaveChanges();
However, we have changed our user entity to have a Guid as a primary key:
public class User
{
DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public Guid ID { get; set; }
public string Username { get; set; }
}
In the database, it is set to data type uniqueidentifier with a "Default Value or Binding" set to (newsequentialid())
After changing this, the Entity Framework code to delete a user throws the following error:
Attaching an entity of type 'Administration.Model.User' 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.
Why is it throwing this error? I suppose it has something to do with the way the primary key is generated, but how can I fix this?
Of course, I could use a linq query and use .Remove, but I want to keep the solution I had using an int value as primary key.
I have existing DB with the following structure:
I'm using EF fluent API to configure relationships between tables:
public GroupEntityConfiguration()
{
HasMany(x => x.Employees).WithRequired().HasForeignKey(x => x.GroupId).WillCascadeOnDelete(true);
}
public EmployeeEntityConfiguration()
{
HasOptional(x => x.InnerGroupMember).WithRequired();
}
With this configuration applied I can add new Employee, new InnerGroupMember or fetch data. The problem appears when I try to remove Employee. Then I get an exception:
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.
As far as I understand above exception is connected with GroupId foreign key. Trying to fix it I'm adding following line to EmployeeEntityConfiguration:
HasKey(x => new { x.Id, x.GroupId});
But after adding it I get another exception which I believe is connected with InnerGroupMember object:
Invalid column name 'Guest_Id'. Invalid column name 'Guest_GroupId'.
If I comment out InnerGroupMember navigation property and remove it's configuration, Employee can be removed.
Could you please give me a hint what I'm doing wrong and how to configure entities to be able to perform all needed operations? Thanks!
I have an existing Group entity and I want to remove Employee from the Employees Group collection:
var group = groupRepository.Find(groupId);
group.RemoveEmployee(employeeId);
_unitOfWork.Save();
RemoveEmployee function inside Group entity looks like this:
public void RemoveEmployee(int employeeId)
{
var employee = Employees.Single(n => n.Id == employeeId);
Employees.Remove(employee);
}
That's why I get an exeption:
The relationship could not be changed because one or more of the foreign-key properties is non-nullable....
After reading this post I wanted to fix it adding HasKey(x => new { x.Id, x.GroupId}); function inside EmployeeEntityConfiguration what leads to the second exception:
Invalid column name 'Guest_Id'. Invalid column name 'Guest_GroupId'.
Actually I made this step (I mean adding HasKey function) without changing DB structure. To make it work, inside Employees table I have to create composite key - combination of Id and GroupId which is also a foreign key. This modification forces changes inside InnerGroupMembers table. DB structure looks now as following:
Now I'm able to remove Employee in a way I showed at the beginning.
Anyway I'm not going for this solution. They are different ways to achieve what I want. Here are some links:
Removing entity from a Related Collection
Delete Dependent Entities When Removed From EF Collection
The relationship could not be changed because one or more of the
foreign-key properties is non-nullable
For one-to-one relationships cascading delete is not enabled by default, even not for required relationships (as it is the case for required one-to-many relationships, that is: The WillCascadeOnDelete(true) in your one-to-many mapping is redundant). You must define cascading delete for a one-to-one relationship always explicitly:
HasOptional(x => x.InnerGroupMember).WithRequired().WillCascadeOnDelete(true);
When you delete an Employee now, the database will delete the related InnerGroupMember as well and the exception should disappear.
I have a problem updating a foreign key in an Entity Framework entity. I am using self tracking entities and have an entity with some relations where the foreign key is also present as a property (one of the new features of EF4). The key (an integer) is marked as Nullable and Concurrency Mode fixed.
Specifically I have an Alarm entity with a many to 0..1 relationship to a confirming user. (a user may confirm several alarms, but an alarm can be confirmed by only zero or one users).
The entity definitions (simplified):
Alarm properties
Id Int32 non-nullable identity entity key
UserId Int32 nullable concurrency mode fixed
Alarm navigation properties
User 0..1 multiplicity
User properties
Id Int32 non-nullable identity entity key
Name String non-nullable
In my self tracking entity the confirming user id is auto-generated as a Nullable just as expected, however if I assign a user to an already persistent alarm and run ApplyChanges, the self tracking context extension tries to set the original value (null) in the EF context (In SetValue in the context extensions), but silently skips that because the ClrEquivalentType of the EdmType is a non-nullable Int32.
Auto-generated extension code:
private static void SetValue(this OriginalValueRecord record, EdmProperty edmProperty, object value)
{
if (value == null)
{
Type entityClrType = ((PrimitiveType)edmProperty.TypeUsage.EdmType).ClrEquivalentType;
if (entityClrType.IsValueType &&
!(entityClrType.IsGenericType && typeof(Nullable<>) == entityClrType.GetGenericTypeDefinition()))
{
// Skip setting null original values on non-nullable CLR types because the ObjectStateEntry won't allow this
return;
}
}
int ordinal = record.GetOrdinal(edmProperty.Name);
record.SetValue(ordinal, value);
}
When the EF later tries to update my alarm I get an OptimisticConcurrencyException because it constructs a WHERE clause in the UPDATE statement where it uses 0 (zero) as the original user foreign key value instead of the correct "is null". (The WHERE clause is part of the EF optimistic concurrency mechanism, where the original values of the properties marked with "fixed" concurrency mode are checked agains the properties in the database).
Are nullable foreign keys / primitive types not fully supported in self tracking entities for EF?
If not, am I forced to use dummy entities instead of null or are there other workarounds?
Update
I have tried to reproduce the problem without STE, but plain EF seems to handle optimistic concurrency well for nullable foreign keys, so this is an STE problem, not an EF problem.
There is numerous issues with self tracking entities, so it is not surprising that there is a glitch here. If I find a workaround that can be implemented in the STE T4 script I will post it here.
Bill Huth posted a working patch at MSDN.
Yes, nullable foreign keys are certainly allowed. We use them all over the place. You don't show your database or model, so it's difficult to be certain what the problem could be, but it sounds as though the Entity Framework cannot figure out the primary key of one of the tables involved. Perhaps you don't have one, maybe because one of them is a view? I'm guessing here, because you don't give much information about what you're doing.
I just started to play with the entity framework, so I decided to connect it to my existing SQL Server CE database. I have a table with an IDENTITY(1, 1) primary key but when I tried to add an entity, I've got the above-mentioned error.
From MS Technet artice I learned that
SQL Server Compact does not support entities with server-generated keys or values when it is used with the Entity Framework.
When using the Entity Framework, an entity’s keys may be marked as server generated. This enables the database to generate a value for the key on insertion or entity creation. Additionally, zero or more properties of an entity may be marked as server-generated values. For more information, see the Store Generated Pattern topic in the Entity Framework documentation.
SQL Server Compact does not support entities with server-generated keys or values when it is used with the Entity Framework, although the Entity Framework allows you to define entity types with server-generated keys or values. Data manipulation operation on an entity that has server-generated values throws a "Not supported" exception.
So now I have a few questions:
Why would you mark key as server-generated if it is not supported and will throw an exception? It's hard to make sence from the quoted paragraph.
When I've tried to add StoreGeneratedPattern="Identity" to my entity's property, Studio complained that it is not allowed. What I'm doing wrong?
What is the best workaround for this limitation (including switching to another DB)? My limitations are zero-installation and using entity framework.
When I hit this limitation, I changed the type to uniqueidentifier
Use uniqueidentifier or generate a bigint/int key value manually is your best option.
Something like this perhaps ...
private static object lockObject = new object();
private static long nextID = -1;
public static long GetNextID()
{
lock (lockObject)
{
if (nextID == -1) nextID = DateTime.UtcNow.Ticks; else nextID++;
return nextID;
}
}
This assumes that you don't generate more than one record per tick during an application run (plus the time to stop and restart). This is a reasonable assumption I believe, but if you want a totally bullet proof (but more complex) solution, go read the highest ID from the database and increment from that.
SQL CE version 4.0 fixed this problem with its Entity Framework provider.
I just hit this issue too... mostlytech's answer is probably the best option, GUIDs are very easy to use and the risk of key collision is very low (although not inexistant).
Why would you mark key as server-generated if it is not supported and will throw an exception? It's hard to make sence from the quoted paragraph.
Because SQL Server (not Compact) supports it, and other third parties may support it too... Entity Framework is not only for SQL Server Compact ;)
In my case, all of my classes have the primary key named "ID"
I created an interface
public class IID
{
public Int32 ID { get; set; }
}
Then I create an extension method
public static Int32 GetNextID<T>(this ObjectSet<T> objects)
where T : class, IID
{
T entry = objects.OrderByDescending(u => u.ID).FirstOrDefault();
if (entry == default(T))
return 1;
return entry.ID + 1;
}
Then when I need a new ID, I just do this:
MyObject myobj = new MyObject();
myobj.ID = entities.MyTable.GetNextID();
the other option is to use SqlCeResultSet on the tables that have the identity column.
i have a primary key named ID with data type of INT32 and have Identity Column
Just do this
MyEntity Entity = new MyEntity();
String Command;
command = "Insert into Message(Created,Message,MsgType)values('12/1/2014','Hello World',5);
Entity.ExecuteStoreCommand(command);
--Exclude the primary key in the insert Statement
--Since the SQLCE do not support system generated keys
--Do not use LINQ because it supplies a default value to 0 for Primary keys that has a
data type of INT