add-type -AssemblyName System.Data.OracleClient

$username = "XXXX"
$password = "XXXX"
$data_source = "XXXX"
$connection_string = "User Id=$username;Password=$password;Data Source=$data_source"

$statement = "select level, level + 1 as Test from dual CONNECT BY LEVEL <= 10"

try{
    $con = New-Object System.Data.OracleClient.OracleConnection($connection_string)

    $con.Open()

    $cmd = $con.CreateCommand()
    $cmd.CommandText = $statement

    $result = $cmd.ExecuteReader()
    # Do something with the results...

} catch {
    Write-Error (“Database Exception: {0}`n{1}” -f `
        $con.ConnectionString, $_.Exception.ToString())
} finally{
    if ($con.State -eq ‘Open’) { $con.close() }
}