import/export data to mobile device using web services

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Hi,
I trying to develope a mobile application that need to import and export
data from sql server mobile (compact) to an oracle database.
I think the best way is to use web services.
I have a web service with a method that access a oracle that base and
returns the number of records from a table.
Every thing is ok but I ned the web service to return a xml containing
the table data.
What is the best way and how ?

thanks in advance (code below).
CODE: web service function

<WebMethod()_
Public Function ola(ByVal str As String) As String
Dim connORA As New System.Data.OracleClient.OracleConnection
connORA.ConnectionString = "Data Source=dbteste;Persist Security
Info=False;User ID=f462;PASSWORD=f462;Unicode=True"
connORA.Open()
Dim cmd As New System.Data.OracleClient.OracleCommand
Dim dr As System.Data.OracleClient.OracleDataReader
cmd.Connection = connORA
cmd.CommandText = "select * from apps order by idapp desc"
cmd.CommandType = CommandType.Text
dr = cmd.ExecuteReader()
While (dr.Read())
Return str & " " & dr.Item("aplicacao").ToString
End While
dr.Close()
cmd.Dispose()
connORA.Close()
End Function