EF Code First issue on CommitTransaction - using Repository pattern - repository-pattern

Question

I am having an issue with EF 4.1 using "Code First". Let me setup my situation before I start posting any code. I have my DBContext class, called MemberSalesContext, in a class library project called Data.EF. I have my POCOs in a seperate class library project called Domain. My Domain project knows nothing of Entity Framework, no references, no nothing. My Data.EF project has a reference to the Domain project so that my DB context class can wire up everything in my mapping classes located in Data.EF.Mapping. I am doing all of the mappings in this namespace using the EntityTypeConfiguration class from EntityFramework. All of this is pretty standard stuff. On top of Entity Framework, I am using the Repository pattern and the Specification pattern.
My SQL Server database table has a composite primary key defined. The three columns that are part of the key are Batch_ID, RecDate, and Supplier_Date. This table as an identity column (database generated value => +1) called XREF_ID, which is not part of the PK.
My mapping class, located in Data.EF.Mapping looks like the following:
public class CrossReferenceMapping : EntityTypeConfiguration<CrossReference>
{
public CrossReferenceMapping()
{
HasKey(cpk => cpk.Batch_ID);
HasKey(cpk => cpk.RecDate);
HasKey(cpk => cpk.Supplier_Date);
Property(p => p.XREF_ID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
ToTable("wPRSBatchXREF");
}
}
My MemberSalesContext class (inherits from DBContext) looks like the following:
public class MemberSalesContext : DbContext, IDbContext
{
//...more DbSets here...
public DbSet<CrossReference> CrossReferences { get; set; }
//...more DbSets here...
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Remove<IncludeMetadataConvention>();
//...more modelBuilder here...
modelBuilder.Configurations.Add<CrossReference>(new CrossReferenceMapping());
//...more modelBuilder here...
}
}
I have a private method in a class that uses my repository to return a list of objects that get iterated over. The list I am referring to is the outermost foreach loop in the example below.
private void CloseAllReports()
{
//* get list of completed reports and close each one (populate batches)
foreach (SalesReport salesReport in GetCompletedSalesReports())
{
try
{
//* aggregate sales and revenue by each distinct supplier_date in this report
var aggregates = BatchSalesRevenue(salesReport);
//* ensure that the entire SalesReport breaks out into Batches; success or failure per SalesReport
_repository.UnitOfWork.BeginTransaction();
//* each salesReport here will result in one-to-many batches
foreach (AggregateBySupplierDate aggregate in aggregates)
{
//* get the batch range (type) from the repository
BatchType batchType = _repository.Single<BatchType>(new BatchTypeSpecification(salesReport.Batch_Type));
//* get xref from repository, *if available*
//* some will have already populated the XREF
CrossReference crossReference = _repository.Single<CrossReference>(new CrossReferenceSpecification(salesReport.Batch_ID, salesReport.RecDate, aggregate.SupplierDate));
//* create a new batch
PRSBatch batch = new PRSBatch(salesReport,
aggregate.SupplierDate,
BatchTypeCode(batchType.Description),
BatchControlNumber(batchType.Description, salesReport.RecDate, BatchTypeCode(batchType.Description)),
salesReport.Zero_Sales_Flag == false ? aggregate.SalesAmount : 1,
salesReport.Zero_Sales_Flag == false ? aggregate.RevenueAmount : 0);
//* populate CrossReference property; this will either be a crossReference object, or null
batch.CrossReference = crossReference;
//* close the batch
//* see PRSBatch partial class for business rule implementations
batch.Close();
//* check XREF to see if it needs to be added to the repository
if (crossReference == null)
{
//*add the Xref to the repository
_repository.Add<CrossReference>(batch.CrossReference);
}
//* add batch to the repository
_repository.Add<PRSBatch>(batch);
}
_repository.UnitOfWork.CommitTransaction();
}
catch (Exception ex)
{
//* log the error
_logger.Log(User, ex.Message.ToString().Trim(), ex.Source.ToString().Trim(), ex.StackTrace.ToString().Trim());
//* move on to the next completed salesReport
}
}
}
All goes well on the first iteration of the outer loop. On the second iteration of the outer loop, the code fails at _repository.UnitOfWork.CommitTransaction(). The error message returned is the following:
"The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges."
In this situation, the database changes on the second iteration were not committed successfully, but the changes in the first iteration were. I have ensured that objects in the outer and inner loops are all unique, adhering to the database primary keys.
Is there something that I am missing here? I am willing to augment my code samples, if it proves helpful. I have done everything within my capabilities to troubleshoot this issue, minus modifying the composite primary key set on the database table.
Can anyone help??? Much thanks in advance! BTW, sorry for the long post!

Answer 1

I am answering my own question here...
My issue had to do with how the composite primary key was being defined in my mapping class. When defining a composite primary key using EF Code First, you must define it like so:
HasKey(cpk => new { cpk.COMPANYID, cpk.RecDate, cpk.BATTYPCD, cpk.BATCTLNO });
As opposed to how I had it defined previously:
HasKey(cpk => cpk.COMPANYID);
HasKey(cpk => cpk.RecDate);
HasKey(cpk => cpk.BATTYPCD);
HasKey(cpk => cpk.BATCTLNO);
The error I was receiving was that the ObjectContext contained multiple elements of the same type that were not unique. This became an issue in my UnitOfWork on CommitTransaction. This is because when the mapping class was instanciated from my DBContext class, it executed 4 HasKey statements shown above, with only the last one for property BATCTLNO becoming the primary key (not composite). Defining them inline, as in my first code sample above, resolves the issue.
Hope this helps someone!