Opf3 Forum: There is already an open DataReader associated with this command problem

RE: There is already an open DataReader associated with this command problem

Mon, 4 Dec 2006 4:30:24 PM GMT

Hi,

the transaction is always rolled back on the storage if no commit comes in and the connection is closed. This happens always if an error occured. Your transaction is always rolled back!

You need to pass the persistent object type to do the reload of the persistent objects. This is at this stage the only way to do it. The problem is that Opf3 does a reload before save. This happens to detect concurrency problems. At the current implementation you would need to do an persistchanges for the different objects types in your objectset.

Are you saving here a bunch of different objects or all of the same type?

RE: There is already an open DataReader associated with this command problem

Mon, 4 Dec 2006 12:17:39 PM GMT

Problem Located....

The Exception is not the original source exception.
The exception being thrown is in AttributeTypeMappingProvider

throw new MappingException(string.Format("Cannot create mapping for type '{0}' without persistent attribute.", type.FullName));

The exception is being passed up through various catch blocks until it reaches my code

public BusinessTransactionData PersistChanges(BusinessTransactionData objects)
{
ObjectContext context = CreateObjectContext();
ObjectSet objs = new ObjectSet();
foreach (object obj in objects.Data)
{
objs.Add(obj);
}
Transaction transaction = context.StartTransaction();
try
{
context.PersistChanges(objs);
transaction.Commit();
return objects;
}
catch (Exception)
{
transaction.Rollback();
throw;
}

}

where the transaction.RollBack() in the catch block causes the DataReader Exception.
This is a problem as rolling back the transaction in case of an error is pretty important.

So my other problem is in the type mapping as the business object is being passed as object rather then its type. Is there anyway I can get around this.

Thanks

RE: There is already an open DataReader associated with this command problem

Mon, 4 Dec 2006 10:02:28 AM GMT

No Change with the latest build.

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:41:53 PM GMT

I could send you the most recent build, if you want. Could you send an e-mail to support@chilisoftware.net

Thank you
Christian

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:40:56 PM GMT

Using SqlServer 2005

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:37:09 PM GMT

Forget my last message. It should work anyway. Wow, this is weird.

Christian

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:35:26 PM GMT

The generic could also cause the problem. Opf3 is doing a reload before doing an update. The code looks like this:

using (ObjectReader reader = e.Context.GetObjectReader(ObjectExpression.CreateLoadExpression(obj)))
{

This T you are seeing here, is the you used in your code. This causes Opf3 to crash. But it's strange that you get this exception you should get another one.

Anyway you need to specify here the type that is persisted. Opf3 will have problems otherwise.

Christian

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:33:04 PM GMT

Are you sure you have no ObjectReader open somewhere in your app, while doing the operation? This happens usually if an ObjectReader is open. An ObjectReader holds an active connection to the database, since it is a cursor.

What's the DB you are using?

Christian

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:22:00 PM GMT

The only real different I really see is in the routine that works the object is being passed as what it is , while in the one that doesn't its being passed as object.

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 4:10:56 PM GMT

Sorry forgot one piece of information. The error only happens if the object is being being updated (doesnt happen for first saves). I think the error is thrown when the object is being re-read from the database.

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 3:38:23 PM GMT

I dont know , in theory they should be the same.
The second is done because I want to save several objects in the same database transaction, but in the example given there is only one object in the list.

The same is happening with any object I throw at this method.

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 3:32:45 PM GMT

Wow! Gets even stranger... The second code is working or not? What's, from your standpoint the difference, that makes it work?

Christian

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 3:24:01 PM GMT

using System;
using System.Collections.Generic;
using BusinessObjects.Data;
using Chili.Opf3;

namespace JobControl.BusinessObjects.Data
{
[Serializable]
[Persistent("Kit")]
public class KitData : BusinessObjectData
{
public KitData()
{
}

#region Fields

private string _name;
private Guid _kitTypeId;

#endregion

#region Properties

///

/// This property is mapped to the "Name" field. Length must be between 0 and 100 characters. Mandatory.
///

RE: There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 3:13:58 PM GMT

This is a weird exception, as Opf3 does dispose all ObjectReader (or IDataReader) immediately after using them.

Could you post the stack trace?

Thanks
Christian

There is already an open DataReader associated with this command problem

Thu, 30 Nov 2006 2:59:53 PM GMT

public BusinessTransactionData PersistChanges(BusinessTransactionData objects)
{
ObjectContext context = CreateObjectContext();
ObjectSet objs = new ObjectSet();
foreach (object obj in objects.Data)
{
objs.Add(obj);
}
Transaction transaction = context.StartTransaction();
try
{
context.PersistChanges(objs);
transaction.Commit();
return objects;
}
catch (Exception)
{
transaction.Rollback();
throw;
}

}

when saving using the above code I get a "there is already an open DataReader associated with this command" This happens even with a single object in the collection.

I am guessing it is the transaction causing this.

if I save the same object with the following code

public T PersistChanges(T obj, bool createTransaction)
{

ObjectContext context = CreateObjectContext();
Transaction transaction = null;
if (createTransaction)
transaction = context.StartTransaction();

try
{
context.PersistChanges(obj);
if (createTransaction)
transaction.Commit();
return obj;
}
catch (Exception)
{
if (createTransaction)
transaction.Rollback();
throw;
}
}

all is fine.

Any Suggestions