EF 5, one to many, more than one table - collections

Question

I'm having a little of trouble with the following classes:
public class TwoVariableDetails
{
public TwoVariableDetails()
{
MovementsPerBlocks = new HashSet<MovementsRow>();
MovementsPerShiftTypes = new HashSet<MovementsRow>();
MovementsPerMachines = new HashSet<MovementsRow>();
MovementsPerShifts = new HashSet<MovementsRow>();
}
[Key]
public Guid TwoVariableDetailsId { get; set; }
[Required]
[MaxLength(50)]
public string Name { get; set; }
[Required]
[MaxLength(1000)]
[DataType(DataType.MultilineText)]
public string Description { get; set; }
public virtual ICollection<MovementsRow> MovementsPerBlocks { get; set; }
public virtual ICollection<MovementsRow> MovementsPerShiftTypes { get; set; }
public virtual ICollection<MovementsRow> MovementsPerMachines { get; set; }
public virtual ICollection<MovementsRow> MovementsPerShifts { get; set; }
}
[Table("Movement")]
public class MovementsRow
{
public MovementsRow()
{
MovementsCells = new HashSet<MovementsCell>();
}
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[CsvField(Ignore = true)]
public Guid MovementId { get; set; }
[Required]
public int RowNo { get; set; }
[Required]
[CsvField(Ignore = true)]
public Guid ModelId { get; set; }
[ForeignKey("ModelId")]
[CsvField(Ignore = true)]
public virtual TwoVariableDetails Model { get; set; }
[TypeConverter(typeof(MovementsCellTypeConverter))]
public virtual ICollection<MovementsCell> MovementsCells { get; set; }
}
[Table("MovementCell")]
public class MovementsCell
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[CsvField(Ignore = true)]
public Guid CellId { get; set; }
[Required]
public int ColumnNo { get; set; }
[Required]
public int Count { get; set; }
[Required]
[CsvField(Ignore = true)]
public Guid MovementId { get; set; }
[ForeignKey("MovementId")]
[CsvField(Ignore = true)]
public virtual MovementsRow Model { get; set; }
}
When I try to save it to the database I get the following error:
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_dbo.Movement_dbo.TwoVariableDetails_ModelId". The conflict occurred in database "aspnet-GreenCranes.UI-20130516", table "dbo.TwoVariableDetails", column 'TwoVariableDetailsId'.
The statement has been terminated.
This is the code I'm using for saving:
twoVariableDetails.TwoVariableDetailsId = Guid.NewGuid();
_context.TwoVariableDetailsModels.Add(twoVariableDetails);
_context.SaveChanges();
My table looks like this:
Movement
- Column
- MovementId
- RowNo
- ModelId(FK, uniqueidentifier, not null)
- TwoVariableDetails_TwoVariableDetailsId(FK, uniqueidentifier, null)
- TwoVariableDetails_TwoVariableDetailsId2(FK, uniqueidentifier, null)
- TwoVariableDetails_TwoVariableDetailsId3(FK, uniqueidentifier, null)
- TwoVariableDetails_TwoVariableDetailsId4(FK, uniqueidentifier, null)
- Keys
- FK_dbo.Movement_dbo.TwoVariableDetails_ModelId
- FK_dbo.Movement_dbo.TwoVariableDetails_TwoVariableDetails_TwoVariableDetailsId
- FK_dbo.Movement_dbo.TwoVariableDetails_TwoVariableDetails_TwoVariableDetailsId1
- FK_dbo.Movement_dbo.TwoVariableDetails_TwoVariableDetails_TwoVariableDetailsId2
- FK_dbo.Movement_dbo.TwoVariableDetails_TwoVariableDetails_TwoVariableDetailsId3
I'm not sure what is the problem with my approach. Should I change the MovementsRow class to have four Model properties and four modelid fk and then use InverseProperty attribute?

Answer 1

MovementsRow.Model belongs to another relationship than the four collections in TwoVariableDetails. That's the reason why you don't have four, but five foreign keys in the database table. When you insert twoVariableDetails into the DB and it contains a MovementRow instance in one of the collections EF expects that its ModelId is set to a Guid that references an existing TwoVariableDetails row - which it doesn't apparently. Hence the exception.
Should I change the MovementsRow class to have four Model properties
and four modelid fk and then use InverseProperty attribute?
I'd say yes. It's probably the best solution. The alternative is to have no Model property at all in MovementRow. It's working but you would not be able to navigate from MovementRow to TwoVariableDetails then.

Answer 2

Your FK_dbo.Movement_dbo.TwoVariableDetails_ModelId is being violated, simply put - the ModelId that the Movement record is using doesn't yet exist in TwoVariableDetails.
If you wanted to keep it simple, and transactional, then you could use TransactionScope along with your database context, save the TwoVariableDetails first in the transaction, and then the records that relate back to it:
using (var context = new MyDbContext())
using (var tranScope = new TransactionScope(TransactionScopeOption.Required) {
// don't save the Movement records yet
twoVariableDetails.TwoVariableDetailsId = Guid.NewGuid();
_context.TwoVariableDetailsModels.Add(twoVariableDetails);
_context.SaveChanges();
// now create the movement records, add them to twoVariableDetails
...
_context.SaveChanges();
// commit the transaction
scope.Complete();
}