Sharepoint 2010 connect to sql server and oracle database

1. Menu add connection strings in c:\inetpub\wwwroot\wss\VirtualDirectories\\web.config
Ex.
/* for sql server and oracle*/
＜connectionStrings＞
＜add name="AdventureWorksConnectionString" connectionString="Data Source=192.168.0.1;Initial Catalog=AdventureWorks;User Id=sa;Password=smpsqladm1" /＞
＜add name="OracleConnectionString" connectionString="Data Source=Ora_TEST;User ID=system;Password=system_pwd" providerName="System.Data.OracleClient" /＞
＜/connectionStrings>

2. In Sharepoint virtual web part ascx file .

＜asp:DetailsView ID="DetailsView1" runat="server" Height="50px" Width="125px"
DataSourceID="SqlDataSource1" EnableModelValidation="True"＞
＜/asp:DetailsView＞

＜asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="＜%$ ConnectionStrings:AdventureWorksConnectionString%＞"
SelectCommand="select count(*) as intUnRead from yourtable"＞
＜/asp:SqlDataSource＞

＜asp:DetailsView ID="DetailsView2" runat="server" Height="50px" Width="125px"
DataSourceID="SqlDataSource2" EnableModelValidation="True"＞
＜/asp:DetailsView＞

＜asp:SqlDataSource ID="SqlDataSource2" runat="server"
ConnectionString="＜%$ ConnectionStrings:OracleConnectionString %＞"
ProviderName="System.Data.OracleClient"
SelectCommand="select count(*) as UnRead from testtable"＞
＜/asp:SqlDataSource＞