Entity Framework : “The underlying provider failed on Open”

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隐瞒了意图╮ 2021-02-13 00:20

When I try to insert a record, I get this error : The underlying provider failed on Open. This error occurs only with IIS and not with VWD 2008\'s webserver. In the EventViewer

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  • 2021-02-13 00:38

    You should create a sql account for your web server to access the aspnetdb database. It is currently using integrated authentication (tries to logon with the identity the web server is using to run the application).

    The example below uses integrated auth. I would use SQL auth though.

    http://msdn.microsoft.com/en-us/library/ff649314.aspx

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  • 2021-02-13 00:41

    Maybe it's too late to answer but i had the same problem.

    I added scope timeout (5 minutes). I let an example.

    Dim varIntervalo As New TimeSpan(0, 5, 0)
    Using varTransaccion As New TransactionScope(TransactionScopeOption.Required, varIntervalo)
        For vari As Integer = 2 To varMatrizDatos.GetUpperBound(0)
            Dim varWhateverAs New TABLE
            varWhatever.ID_TABLE = something
            varWhatever.DESC_TABLE = something else
            varWhatever.DATE_TABLE = CDate(Now.Date)
    
            varEntidades.AddToTABLESet(varWhatever)
            varEntidades.SaveChanges()
        Next
        varTransaccion.Complete()
    End Using
    

    Maybe this code could be improve.

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  • 2021-02-13 00:42

    I was getting the same problem and after doing debugging i saw that i am creating the new instance of DB Entity on every action and making new instance of Db Entity means openning new connection with db.

    Below is the code :

    Private tmpConnection As New DbModel.DbEntities
    

    so by calling the variable again and again its creating new instance of DbEntites and opening new connection to db.

    so i write a small function for this and that solved my problem. Now no more error.

    Private tmpConnection As DbModel.DbEntities
    
    Public Function dbCon() As DbModel.DbEntities
    
        If tmpConnection IsNot Nothing Then
    
            If tmpConnection.Connection.State = ConnectionState.Closed Then
    
                Try
                    tmpConnection.Connection.Open()
                    Return tmpConnection
                Catch ex As Exception
                    My.Response.Redirect("dberror.aspx")
                End Try
    
            Else
    
                Return tmpConnection
    
            End If
    
        Else
    
            tmpConnection = New DbModel.DbEntities
    
            Try
                tmpConnection.Connection.Open()
                Return tmpConnection
            Catch ex As Exception
                My.Response.Redirect("dberror.aspx")
            End Try
    
        End If
    
        Return Nothing
    End Function
    

    and last thing in your connectionstring please add "Connect Timeout=30;"

    thats working so perfect for me

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  • 2021-02-13 00:46

    Using new instance of DB Entity on every action should not physically create connection to your SQL server. Entity Framework will use connection pool created for your (process, app domain, connection string) as configured in your connection string to avoid creating new connections.

    This issue is very environmental and tweaking parameters (in your conn string) like below should resolve the problem-

    Min Pool Size=1;

    Max Pool Size=100; // default

    Connect Timeout=15; // in seconds

    Pooling=true;

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  • 2021-02-13 00:57

    Add the below attribute in the Connection string which you have given.

    <add 
         name="ASPNETDBEntities" 
         connectionString="metadata=res://*/Models.FriendList.csdl|
                           res://*Models.FriendList.ssdl|res://*/Models.FriendList.msl;
                           provider=System.Data.SqlClient;provider connection string=&quot;
                           Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\ASPNETDB.MDF;
                           Integrated Security=True;Connect Timeout=30;
                           User Instance=True;
                           MultipleActiveResultSets=True&quot;" 
         ProviderName="System.Data.EntityClient" 
         User Instance="False"/>
    
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  • 2021-02-13 01:01

    In my case, I was using Sql CE, and my connection string was set up with an absolute path instead inf the |DataDirectory| variable. Changed this and it began working on the server.

    Obviously, it worked fine on the development machine.

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