How do I create a download link knowing the uploaded file ID? I've a column in database containing the IDs of the files uploaded using a managed file form field.

How do I create a link to the uploaded file knowing its file ID?

EDIT : 
The obvious solution doesn't work for me , i'm using another table where i put my Fids .

this is the warning i got everytime :
Notice: Trying to get property of non-object in Affichage_form() (line 188 of C:\wamp64\www\Gestion_tickets_licences\sites\all\modules\Recherche\Recherche.module). &lt;&lt; 188 : $uri= $file->uri; >>

Solution : Thank you for you help .
my solution for my problem is , Once I upload the file , I create the url. Instead of saving Fid , I save the url , It worked .For the download link , I used Alen syntax and it worked great .
First, load the file using file_load(FILE_ID) and get URI like below:

$file = file_load(1);
$uri = $file-&gt;uri;


After that generate link using file_create_url();

$url = file_create_url($uri);


Get file name also: 

$filename  = $file-&gt;filename;


And finally, create a link using l().

l(t($filename), $url);


and output will be like &lt;a href="http://d7.local/sites/default/files/pictures/picture-6.png"&gt;picture-6.png&lt;/a&gt;