Hi Guys,

Using ES version: 2007.0.913.0

         MyGeneration version: 1.2.0.7

         Oracle XE (10g free edition)

Attempting to load a single entity, but two or more are being returned from the database. I have wrapped the call to Query.Load in a Try-Catch block, but the 'An entity can only hold one record of data' exception is not being propagated up to the Load call. The call to Me.PopulateEntity(table) in OnQueryLoad, is failing with an Unhandled Exception and the RowCount check is not executed in order to throw the exception.

I did not use the 'Custom Base Class' option in generating my class, so it inherits from esEntity. The following is the code I am trying:

 _543Transaction = New Transaction

        _543Transaction = SetCommonWhereConditions(_543Transaction)

        With _543Transaction.Query
            .Where(.AccountNo.Equal(acct))
            .Where(.SubAccountNo.Equal(subAcct))
            .Where(.TransTypeCd.Equal("Z"))
            Try
                If .Load() = False Then
                    _543Transaction.AddNew()
                    _543Transaction.AccountNo = acct
                    _543Transaction.SubAccountNo = subAcct
                    _543Transaction.TransactionDate = CType("01/01/2007", Date)
                    _543Transaction.TransactionAmt = 5
                    _543Transaction.TransTypeCd = "Z"
                    _543Transaction.Save()
                Else
                    _543Transaction.TransactionAmt = _543Transaction.TransactionAmt.Value + 5
                    _543Transaction.Save()
                End If
            Catch ex As Exception
                MessageBox.Show(ex.ToString)
            End Try

        End With

'The Unhandled Exception occurs on the  Dim dataFound as Boolean = Me.PopulateEntity(table) line

Protected Function OnQueryLoaded(ByVal table As DataTable) As Boolean
            Dim dataFound as Boolean = Me.PopulateEntity(table)

            If Me.RowCount > 1 Then
                throw New Exception("esTransaction can only hold one record of data")
            End If
           
            Return dataFound
        End Function   

What am I Missing something?  
 

I believe this is the issue. A collection can hold many records, a single entity can hold only 1 row as it represents only a single row. You're Query.Load() is returning more than one record from the database, thus the error. Here's what you can do, run the same query on one of your TransactionCollections and see how many rows come back, if it's more than 1 you either need to adjust the query or use a collection.

Thanks for the reply Mike. I understand what you are saying, but in this instance I would rather use a single entity. The case when two rows would be returned is very rare, but it is a situation that needs to be handled gracefully so that the user can be warned that there is bad data in the database.

I don't understand why the exception is not caught in the PopulateEntity(table) method?

Why have the RowCount check if the code is never executed? It would be nice to be able to catch the exception on Query.Load so it can be handled properly.

RowCount comes off of esEntityData which both esEntity and esEntityCollection inherit from. True, RowCount can never be more than one on an esEntity based object but there's no harm in that. We do throw the exception to warn you that your query returned more than one row which doesn't really mean there is bad data in the database, it just means your query returned more than one row. I guess the thing is when you decide to use the single entity to perform a query you need to be sure you're fetching just one row (but we throw the exception to make sure your aware that it didn't). I feel like our mechanism worked well in this case, it let you know that more than one row was returned.

You should be able to catch that exception?  

I am not able to catch the exception, that is the problem...

I get an UnhandledException on the call to PopulateEntity(table), therefore the exception is not propagated back up the stack to the Query.Onload call.

The throw New Exception("esTransaction....line is not executed because of the UnhandledException. I could wrap the call to Me.PopulateEntity in a Try Catch block, but that is in the generated class and would be overwritten when regening the class. 

Okay, I went to fix this issue, ran this code and ...

try
{
    Employee emp = new Employee();
    emp.Query.Load();
}
catch (Exception ex)
{
    string s = ex.Message;
}

It caught the "An Entity can only hold 1 record of data". Perhaps I don't understand the issue after all?

The exception looks to be in his OnQueryLoaded function not the try catch block you tested. I'm not sure what event the OnQueryLoaded function is handling though.

Hmmm...strange. I get different results. Below is the generated code for the OnQueryLoaded function of the Entity class. Note that the OnQueryLoaded function contains no Try Catch block and that the call to PopulateEntity(table) is where the exception occurs. It seems the RowCount check is being made in the PopulateEntity function and the exception being thrown from there as well. Using EntitySpaces.Core version 2007.0.913.0

Protected Function OnQueryLoaded(ByVal table As DataTable) As Boolean
			Dim dataFound as Boolean = Me.PopulateEntity(table)

			If Me.RowCount > 1 Then
				throw New Exception("esGstCodeDesc can only hold one record of data")
			End If
			
			Return dataFound
        End Function

This is still a problem for me and other developers (not to mention our users).

I peeked into the EntitySpaces.Core  - PopulateEntity - method and noticed that RowCount is checked and an Exception thrown if RowCount > 1.

The generated class OnQueryLoaded method calls PopulateEntity and has no way of handling the exception thrown...this is why I get the Unhandled Exception and all the problems that arise because of it.

This seems like an easy fix that would really help out our users.

It is not a problem of me using a single entity when I should be using a collection, our system sometimes has times when more than one row is returned when expecting only one, and we need to know when this happens to deal with it appropriately.

Thanks,

Pete 

As to the difference, Mike has the source code, has the projects in his solution, and is referencing the projects. You are referencing just the compiled assemblies. Fortunately, this is just an inside VS while debugging issue. It does not happen in Release mode, it does not happen in Debug mode if you "Start without debugging", and will not occur outside VS when running the executable from either \bin\Debug or \bin\Release.

Currently, you have 3 options until we get a fix out:

1. Just click "Continue" in the debugger, and your Try/Catch block will be hit.
2. Go to Tools -> Options -> Debugging -> General, and un-check "Enable Just My Code".
3. Make a simple template change, and regenerate.

For the EntitySpaces -> C# -> Generated -> EntitySpaces - esEntity(C#) template, add the attribute line above line 491 so it looks like this:

[System.Diagnostics.DebuggerNonUserCode]
protected bool OnQueryLoaded(DataTable table)

For the EntitySpaces -> VB -> Generated -> EntitySpaces - esEntity(VB.NET) template, add the attribute line above line 474 so it looks like this:

<System.Diagnostics.DebuggerNonUserCode> _
Protected Function OnQueryLoaded(ByVal table As DataTable) As Boolean