Generate passwords encrypted with bcrypt in an already existing user table

Try it with this code for selected records. A field "Passwortkopie" is used for saving the password without encryption as a way back in case something went wrong. $altespasswort is the old password, $verschlpasswort is the encrypted version.
`$sql="alter table Benutzer add Passwortkopie varchar(60);";
DB::Exec($sql);
$sql="update Benutzer set Passwortkopie=Passwort;";
DB::Exec($sql);
$sql="alter table Benutzer modify Passwort varchar(60);";
DB::Exec($sql);
while($record = $button->getNextSelectedRecord())
{
$altespasswort=$record["Passwort"];
$verschlpasswort=getPasswordHash($altespasswort);
//$verschlpasswort=password_hash($altespasswort,PASSWORD_BCRYPT);
$email=$record["Email"];

$sql="update Benutzer set Passwort='".$verschlpasswort."' where Email='".$email."';";
DB::Exec($sql);

//$valid=password_verify ( $altespasswort , $verschlpasswort ) ;
//$sql="update Benutzer set Gruppe='".$valid."' where Email='".$email."';";
//DB::Exec($sql);
}
alert("Verschlüsselung erfolgt.");

`

In which event do I have to add that code? Is there no way that with one code you can generate all the passwords without having to go through one by one?

It is the code for a custom button and it changes the passwords for all marked users (getNextSelectedRecord) ...