Dim con As ADODB.connection
    Dim rs As ADODB.Recordset
    Dim query As String
    Set con = New ADODB.connection
    Set rs = New ADODB.Recordset
    '---- Replace below highlighted names with the corresponding values
    strCon = "Driver={Microsoft ODBC for Oracle}; " & _
    "CONNECTSTRING=(DESCRIPTION=" & _
    "(ADDRESS=(PROTOCOL=TCP)" & _
    "(HOST=127.0.0.1)(PORT=1521))" & _
    "(CONNECT_DATA=(SID=xe))); uid=system; pwd=root;"
    '---  Open   the above connection string.
    MsgBox (strCon)
    con.Open (strCon)
    '---  Now connection is open and you can use queries to execute them.
    '---  It will be open till you close the connection

   conn = "UID=system;PWD=root;DRIVER={Microsoft ODBC for Oracle};" _
           & "SERVER=127.0.0.1;"

   Set Cn = New ADODB.connection

   With Cn
       .ConnectionString = conn
       .CursorLocation = adUseClient
       .Open
   End With