php - PDO - Dynamic Query Building -

is somehow possible built dynamic query pdo?

description:
have following function:
function

savecontent($roundid,$answer,$question_de,$question_en,$files_1_1,$files_1_2,$files_2_1,$files_2_2,$files_3_1,$files_3_2) {          $sql_pictures = "             update ".dbprefix."pictures             set                 file_1_static=:files_1_1,                 file_1_animation=:files_1_2,                 file_2_static=:files_2_1,                 file_2_animation=:files_2_2,                 file_3_static=:files_3_1,                 file_3_animation=:files_3_2                             roundid=:roundid";         try {             $db = self::getconnection();             $stmt_pictures = $db->prepare($sql_pictures);              $stmt_pictures->bindparam("roundid", $roundid);             $stmt_pictures->bindparam("files_1_1", $$question_de);             $stmt_pictures->bindparam("files_1_2", $question_en);             $stmt_pictures->bindparam("files_2_1", $roundid);             $stmt_pictures->bindparam("files_2_2", $$question_de);             $stmt_pictures->bindparam("files_3_1", $question_en);             $stmt_pictures->bindparam("files_3_2", $question_en);              $stmt_pictures->execute();             $db = null;             return true;         } catch(pdoexception $e) {             echo $e->getmessage();         }      }   

the important part in "sql_pictures". i'm calling function passing necessary data function, this:

if (isset($_post['save'])) {                     $savecontent = $helper->savecontent(                 $_post['roundid'],                 $_post['answer'],                 $_post['question_de'],                 $_post['question_en'],                 $_files["files_1_1"],                 $_files["files_1_2"],                 $_files["files_2_1"],                 $_files["files_2_2"],                 $_files["files_3_1"],                 $_files["files_3_2"]             );           } 

as of maybe notice, it's multiple file upload.
main problem is, don't want update fields when either string empty (not set) or value didn't changed (i.e $files_1_1 didn't changed or empty).

how can achieve that?

other question:
maybe better use

<input type="file" name="files[]" id="file" />   

instead of

<input type="file" name="files_1_2" id="file" /> 

for each input field?
, how can refactor function then? i'm sitting on many hours, no clue. hint nice! :)

thanks!

for insert/update queries dynamic query building quite simple task. create array key names equal field names , corresponding values , process them in loop.

i don't want update fields when either string empty (not set) or value didn't changed

the last 1 doesn't matter. if value didn't change - won't changed in table either.
other values create array values suits (i.e not empty) , use helper function create set statement dynamically. can use 1 pdo tag wiki example

other question:

personally prefer files_1, files_2, files_3... way lets me iterate on $_files array using simple foreach