Hi

I have a problem,

I make a web site with Visiual Studio 2005 in C#. I use Sql server for my database.

Web site work on my local machine without any problem.

Web site wast work since yesterday at server machine. (It was work before)

I get an error message like this;

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: An error occurred creating the configuration section handler for system.data: Column 'InvariantName' is constrained to be unique.  Value 'MySql.Data.MySqlClient' is already present.

Source Error:

Line 106:    <add name="LocalMySqlServer" connectionString="" />
Line 107:  </connectionStrings>
Line 108:  <system.data>
Line 109:    <DbProviderFactories>
Line 110:      <add name="Odbc Data Provider" invariant="System.Data.Odbc" description=".Net Framework Data Provider for Odbc" type="System.Data.Odbc.OdbcFactory, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />

I don't use mysql and I didn't change anyting at datatables, classes or dadabase last4 days.

This error usually means that you are trying to insert data into the database which the column is set to be unique.

For example, if you have an ID field that is set to be unique, you cannot insert another row with the same ID. 

I would check the database content to make sure you do not have any duplicate data there.

But error comes from startup. There is no use of database and it works on local and another server.

When I was delete dataset xsd web page start normaly.

This problem occur when I start to web page with dataset in app_Code. If I delete dataset.xsd there will no problem (except I cant use database.)

HI, Zadeh: 

To overcome this problem you need to add the following string to your web.config as well:

We are marking this issue as "Answered". If you have any new findings or concerns, please feel free to unmark the issue.
Thank you for your understanding!