在数据库的所有列中只插入一个值

Question

require_once 'core.php' ;

try {
 $db = new PDO("mysql:host=$host;dbname=$dbname",$user,$password) ;
 $db -> setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);

 $a = array(
    'name' => 'rocky',
    'password' => '12345' ,
    'age' => '22'
    ); 
 $c = implode(",",array_keys($a) ) ;
 $f = ":".implode(" , :",array_keys($a));

  $db->beginTransaction();
  $query = $db->prepare("INSERT INTO try ($c) VALUES ($f)");
  foreach ($a as $key => $value) {
        $query->bindParam(":".$key,$value,PDO::PARAM_STR) ;
  } 
  $query->execute() ;
  $db->commit() ;


} catch(PDOException $e){
die($e->getMessage()) ;
} 

in database only one which is age value insert in name ,password, age column same value like 22 ,22 ,22

Answer 1

Problem is in bindParam function:

$db->beginTransaction();
$query = $db->prepare("INSERT INTO try ($c) VALUES ($f)");
foreach ($a as $key => $value) {
    $query->bindParam(":".$key,$value,PDO::PARAM_STR) ;
} 
$query->execute() ;
$db->commit() ;

Reading bindParam manual:

Unlike PDOStatement::bindValue(), the variable is bound as a reference and will only be evaluated at the time that PDOStatement::execute() is called.

This means that when you do execute - all binded variables are set to last $value value which is the last value of array and is 22.

So, use bindValue:

$db->beginTransaction();
$query = $db->prepare("INSERT INTO try ($c) VALUES ($f)");
foreach ($a as $key => $value) {
    $query->bindValue(":".$key, $value, PDO::PARAM_STR) ;
} 
$query->execute() ;
$db->commit() ;