'The specified store provider cannot be found in the configuration, or is not valid.'

Question

Help me please.
when I run the program. It' can't connect To Oracle database .
but I use Server explorer query .It's work

project asp.net framwork 4.8 MVC
Entity V 5.0

Answer 1

the error say the provider specified in the connection string, is not built into the project. you probably need to add oracle support via a nuget package. see the oracle docs for proper package.

Answer 2

but the error indicates that you are probably using EF/AdoDb, not the native OracleClient (the OracleClient connection string does not have a provider). you probably want the Oracle Data Provider for .net. This has a driver for Linq to Sql and Entity Framework.

https://docs.oracle.com/database/121/ODPNT/install.htm#ODPNT0006

Answer 3

Hi @Nattiko Mattiphong ,
In application pools and advanced settings. Look at "Enable 32-bit applications" and see if it's enabled.
Try changing the C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\Machine.config <system.Data> tag as follows:

<system.data>  
<DbProviderFactories>  
    <add name="ODP.NET, Unmanaged Driver"  invariant="Oracle.DataAccess.Client" description="Oracle Data Provider for .NET, Unmanaged Driver" type="Oracle.DataAccess.Client.OracleClientFactory, Oracle.DataAccess, Version=4.121.1.0, Culture=neutral, PublicKeyToken=89b483f429c47342" />  
<add name="ODP.NET, Managed Driver" invariant="Oracle.ManagedDataAccess.Client" description="Oracle Data Provider for .NET, Managed Driver"  type="Oracle.ManagedDataAccess.Client.OracleClientFactory, Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342" />  
</DbProviderFactories>  
</system.data>  

add this line in web.config for web app, or in App.config if it is console App. under <configurations> </configurations> tag (Under not inside).

<system.data>  
    <DbProviderFactories>  
      <add name="ODP.NET, Managed Driver" invariant="Oracle.ManagedDataAccess.Client" description="Oracle Data Provider for .NET, Managed Driver"  type="Oracle.ManagedDataAccess.Client.OracleClientFactory, Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342" />  
    </DbProviderFactories>  
</system.data>  

Configuring Oracle Data Provider for .NET

Best regards,
Lan Huang

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