c#访问各数据库的providerName各驱动

在machine.config（C:/WINDOWS/Microsoft.NET/Framework/v2.0.50727/CONFIG）文件中有这么一段：

    <system.data>
        <DbProviderFactories>
            <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"/>
            <add name="OleDb Data Provider" invariant="System.Data.OleDb" description=".Net Framework Data Provider for OleDb" type="System.Data.OleDb.OleDbFactory, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
            <add name="OracleClient Data Provider" invariant="System.Data.OracleClient" description=".Net Framework Data Provider for Oracle" type="System.Data.OracleClient.OracleClientFactory, System.Data.OracleClient, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
            <add name="SqlClient Data Provider" invariant="System.Data.SqlClient" description=".Net Framework Data Provider for SqlServer" type="System.Data.SqlClient.SqlClientFactory, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
            <add name="Microsoft SQL Server Compact Data Provider" invariant="System.Data.SqlServerCe.3.5" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=3.5.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"/></DbProviderFactories>
    </system.data>

如果为Aceess数据库--->providerName="System.Data.OleDb"

如果为Oracle 数据库--->providerName="System.Data.OracleClient"或者providerName="Oracle.DataAccess.Client"

如果为sql     数据库--->providerName="System.Data.SqlClient"

另：

providerName="System.Data.Odbc"可用于所有数据库配置。

则如果为mysql  数据库--->providerName="System.Data.Odbc"