如何在Openerp中下载附加到我的表单的文件

I have a file on my Server.I want to download the file in Openerp.If we take a "Back Up" of Database,the file will be downloaded and stored on local machine. I want to do the same functionality but for a file which i have uploaded into a form in Openerp.AS of now I'm saving the file as a binary field in my database, it will complex my searches operation.IN order to prevent it,I want to Download that file(like database back up file) on to my machine. Can any one please say me how to do it.Thanks in advance.I have a file on my Server.I want to download t