Devart Forums

john.valentine

StanislavK wrote:Thank you for the helpful link. At the moment, the PLINQ support is unavailable, but we will analyze the possibility of implementing it. We will report here about the results.

Please note that the parallel execution can help only if several sub-queries are used (like when tables from different data contexts are joined), the data fetch won't speed up in the case of simple queries.

Thank you for the straight answer regarding PLINQ. We are using the dotConnect for Oracle product and are pretty happy with it, that said, our overall performance marks could be better. Combining PLINQ with an upgrade to .NET 4 could help get us there, but I am not comfortable recommending that kind of upgrade just yet.

I look forward to receiving more communication on this topic in the future.

Kind Regards,

John

john.valentine

The August 2010 issue of Visual Studio magazine does an expose (pp. 14) on how to exploit multi-core processors with .NET 4 and Visual Studio 2010. In the article it plainly shows PLINQ working with an actual (Northwind) database - so PLINQ is not just for use with LINQ to XML and LINQ to Objects.

I highly recommend this magazine by the way, it is an excellent source of information for developers who like to stay on top of new and emerging Microsoft technologies and development solutions.

So the question was, and still is, can the Devart dotConnect products take advantage of PLINQ?

Inquiring minds would like to know...

john.valentine

I sent the email a few minutes ago. Thanks!

john.valentine

AndreyR wrote:Your code seems to be correct.
Could you please make and send us a test project illustrating the issue?
This will help us in our investigation.

After seeing your message, I spent the rest of the day creating a sample solution for you. It is not pretty, but it does show the problem. Where do I send the code?

Thanks!

john.valentine

Thanks for the update. We came to the same conclusion.

Since we are using the MVP pattern as a part of our development methodology, we need to wrap all the providers into our own classes and move all the provider method calls in our various presenters.

more on MVP:
http://en.wikipedia.org/wiki/Model-view-presenter

We chose to use the Oracle classes and override them since they use the M$ classes as base classes. They also follow a more traditional table structure. This will be helpful if our customers choose to use SQL Server in the future.

Please have a look at our current problem if you get the chance.
http://www.devart.com/forums/viewtopic.php?t=17659

Thanks!

john.valentine

Hey Devart,

We have been having a lot of trouble with the Devart dotConnect for Oracle. Both of the past 2 versions have been giving us issues with regard to our custom providers.

The Devart providers are not good enough for us as they depart from the standard .NET provider too much. It would be a lot of extra work to switch to SQL Server if our customer ever has the need. So we decided to use the Oracle Providers.

We created several new classes that inherit from the System.Web.Security classes from M$. Then using the repository pattern, we built classes to override the M$ classes and perform our own implementation using the Devart.Data.Linq.DataContext.

The problem with our solution is that the DataContext keeps throwing random errors. So today, I branched and upgraded my code to use the new 5.60 version. I am still getting random problems with IDataReader errors, and Db Connection errors where the connection appears to either be open or closed when it shouldn't. I am also getting some nebulous Stored Procedure failed errors.

All in all we are not real happy. We need someone to take control of this over at Devart and contact us as soon as possible so we can move forward.

Our Config:
- Oracle 10g
- Devart 5.60
- VS 2008 Pro .NET 3.5

The Stack Trace:

Code: Select all

Devart.Data.Linq.LinqCommandExecutionException was unhandled by user code
  Message="Error on executing DbCommand."
  Source="Devart.Data.Linq"
  StackTrace:
       at Devart.Data.Linq.LinqCommandExecutionException.a(String A_0, Exception A_1)
       at Devart.Data.Linq.Provider.DataProvider.a(b A_0, Object[] A_1, Object[] A_2, Object A_3)
       at Devart.Data.Linq.Provider.DataProvider.a(b A_0, Object[] A_1)
       at Devart.Data.Linq.Provider.DataProvider.h(Expression A_0)
       at Devart.Data.Linq.Table`1.System.Linq.IQueryProvider.Execute[TResult](Expression expression)
       at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source, Expression`1 predicate)
       at MyProject.Model.Data.Oracle.Repositories.UserRepository.Exists(String userName) in C:\SourceControl\MyProject\trunk\Assemblies\MyProject.Model.Data\Oracle\Repositories\UserRepository.cs:line 111
       at MyProject.Security.RoleProvider.GetRolesForUser(String username) in C:\SourceControl\MyProject\trunk\Assemblies\MyProject.Security\RoleProvider.cs:line 143
       at System.Web.Security.RolePrincipal.IsInRole(String role)
       at System.Web.Configuration.AuthorizationRule.IsTheUserInAnyRole(StringCollection roles, IPrincipal principal)
       at System.Web.Configuration.AuthorizationRule.IsUserAllowed(IPrincipal user, String verb)
       at System.Web.Configuration.AuthorizationRuleCollection.IsUserAllowed(IPrincipal user, String verb)
       at System.Web.Security.UrlAuthorizationModule.OnEnter(Object source, EventArgs eventArgs)
       at System.Web.HttpApplication.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
       at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
  InnerException: System.InvalidOperationException
       Message=""
       Source="Devart.Data.Oracle"
       StackTrace:
            at Devart.Data.Oracle.OracleUtils.c(String A_0)
            at Devart.Data.Oracle.OracleDataReader.b()
            at Devart.Data.Oracle.OracleDataReader..ctor(aa A_0, aa[] A_1, OracleConnection A_2, CommandBehavior A_3, Int32 A_4, Int32 A_5, Int32 A_6, NumberMappingCollection A_7, Boolean A_8)
            at Devart.Data.Oracle.OracleDataReader..ctor(aa A_0, aa[] A_1, OracleConnection A_2, CommandBehavior A_3, Int32 A_4, Int32 A_5, NumberMappingCollection A_6, Boolean A_7)
            at Devart.Data.Oracle.OracleCommand.InternalExecute(CommandBehavior behavior, IDisposable disposable, Int32 startRecord, Int32 maxRecords, Boolean nonQuery)
            at Devart.Common.DbCommandBase.ExecuteDbDataReader(CommandBehavior behavior, Boolean nonQuery)
            at Devart.Common.DbCommandBase.ExecuteDbDataReader(CommandBehavior behavior)
            at System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader()
            at Devart.Data.Linq.Provider.DataProvider.a(b A_0, Object[] A_1, Object[] A_2, Object A_3)
       InnerException:

The Code:

Code: Select all

        #region Private Member Variables

        NPDataContext context = null;

        #endregion

        #region Constructors

        public UserRepository()
        {
            context = new NPDataContext();
        }

        #endregion

Code: Select all

public bool Exists(string userName)
{
    var _user = context.OraAspnetUsers.FirstOrDefault(u => u.Username == userName);
    return _user != null ? true : false;
}

Kind Regards,

John

john.valentine

I need to be able to inherit from the DBMembershipProvider so I can fit the dotConnect features into my MVP project.

We would like to move the function calls from our view project into our presenter project.

I spiked this as a possibility using the Microsoft Provider model, but I guess you guys are doing something a little different.

The following code should be all that I need unless I want to extend your base functionality.

Code: Select all

public class MembershipProvider : Devart.Common.Web.Providers.DbMembershipProvider
    {        
        #region Public Constructors

        public MembershipProvider(string defaultName, string defaultDescription, System.Data.Common.DbProviderFactory provider)
            : base(defaultName, defaultDescription, provider)
        {

        }

        #endregion

    }

The error I get looks like this:

Code: Select all

'MembershipProvider' does not implement inherited abstract member 'Devart.Common.Web.Providers.DbMembershipProvider.GetUsersProvider()'

Where can I find the documentation for extending all DevArt the providers?

Thanks!

John

Devart Forums

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August 2010 issue of Visual Studio Magazine

LinqCommandExecutionException

DBMembershipProvider Inheritance