IsolationLevel

We are getting the following exception when calling SaveChanges on the unit of work. We are using an Oracle database. Our unit of work is created using UnitOfWorkScopeBase<SupplyUnitOfWork> by calling _context = new LightSpeedContext<SupplyUnitOfWork>("DefaultContext").

 Any thoughts on why we need to specify ReadCommitted or Serializable?

System.ArgumentException was unhandled by user code
  Message="IsolationLevel must be ReadCommitted or Serializable\r\nParameter name: isolationLevel"
  Source="Oracle.DataAccess"
  ParamName="isolationLevel"
  StackTrace:
       at Oracle.DataAccess.Client.OracleConnection.BeginTransaction(IsolationLevel isolationLevel)
       at Oracle.DataAccess.Client.OracleConnection.System.Data.IDbConnection.BeginTransaction(IsolationLevel isolationLevel)
       at Mindscape.LightSpeed.UnitOfWork.BeginTransaction(IsolationLevel isolationLevel)
       at Mindscape.LightSpeed.UnitOfWork.SaveChanges(Boolean reset)
       at Mindscape.LightSpeed.UnitOfWorkBase.SaveChanges()
       at XXX.YYY.Model.Repository.SaveChanges() in C:\XXX\Projects\iYYY\.NET\YYY\Model\Repository.cs:line 121
       at XXX.YYY.Controllers.SupplierProfileDetailController.Save(Int32 id) in C:\XXX\Projects\iYYY\.NET\YYY\Controllers\Controllers\Controls\UserControls\SupplierProfileDetailController.cs:line 74
       at XXX.YYY.Views.Controls.UserControls.SupplierProfileDetail.Save_Click(Object sender, EventArgs e) in C:\XXX\Projects\iYYY\.NET\YYY\Views\Controls\UserControls\SupplierProfileDetail.ascx.cs:line 66
       at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
       at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
  InnerException:
 

Not sure exactly what's happening there, but we have found that Oracle can be quite sensitive about transactions.  Are you using an ambient TransactionScope?  We've found that Oracle can have problems with those.  If so, try replacing it with a call to IUnitOfWork.BeginTransaction() (you shouldn't need to specify an IsolationLevel as Oracle will supply its own default).

Because of resolving another problem, I just found out that all along we've been using Lightspeed with MS data provider for Oracle (shame on me for not seeing it before :( ). Not sure how it happened, but the context initilization was
context.DataProvider = DataProvider.Oracle9; instead of
context.DataProvider = DataProvider.Oracle9Odp;

But, after just switching to ODP my first very simple test method of entering one record immediately "broke" with "System.ArgumentException: IsolationLevel must be ReadCommitted or Serializable" (see also stack trace below).
The test method is really a very simple operation, no transactions initiated or aynthing.
                EventType evType = new EventType();
                evType.Name = "Test";
                evType.Description = "Testing";
                uow1.Add(evType);
                uow1.SaveChanges();

BTW, if it makes a difference, we (trying to :) use the latest ODP.NET version 11.1.0.6.20. From version conflicts with Lightspeed referenced Oracle.DataAccess.dll I think you're using the ODP.NET version which is shipped with database server 10g installation.

Stack trace at Exception:
Oracle.DataAccess.Client.OracleConnection.BeginTransaction(IsolationLevel isolationLevel)
Oracle.DataAccess.Client.OracleConnection.System.Data.IDbConnection.BeginTransaction(IsolationLevel isolationLevel)
Mindscape.LightSpeed.UnitOfWork.BeginTransaction(IsolationLevel isolationLevel)
Mindscape.LightSpeed.UnitOfWork.SaveChanges(Boolean reset)

Call me crazy, but playing whole day with different test methods because of that projection issue, and suddenly ODP provider is working. I am really not sure why, that same method is passing now. The only remotely reasonable explanation is that I was recompiling some stuff and references, but really no real code change which should affect something like this...
Really not sure what to say... I probably need a rest, too much testing :(