插入字符串时缺少前导零

Question

I actually get very mad about PHP and SQLite3 and the way some of my strings behave there.
I try to save opening hours but in strings instead of numeric to prevent problem with leading zeros (and still have it now haha... -.-).
Hours and minutes have their own column but when I insert '0x' the zero is gone and whatever x is, is left in the database. :/
Im sure im just missing some little damn part somewhere...
I already checked the INSERT-statement but found nothing at all.
Example for an insert string:
INSERT INTO opening INSERT INTO opening (start_day, end_day, start_hour, start_minute, end_hour, end_minute) VALUES('Montag', 'Freitag', '00', '00', '01', '00')
But the output is:

11|Montag|Freitag|0|0|1|0

Part of the Code:

class Database_Opening_Hours extends SQLite3{
    function __construct() {
        if(!file_exists("../../data/opening_hours/opening_hours.sqlite")){
            $this->open("../../data/opening_hours/opening_hours.sqlite");
            $this->exec('CREATE TABLE opening (id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, start_day STRING, end_day STRING, start_hour STRING, start_minute STRING, end_hour STRING, end_minute STRING)');
        }
        else{
            $this->open("../../data/opening_hours/opening_hours.sqlite");
        }
    }
}
$db = new Database_Opening_Hours();
$insert = "INSERT INTO opening (start_day, end_day, start_hour, start_minute, end_hour, end_minute) VALUES('".htmlspecialchars($_GET["start_day"])."','".htmlspecialchars($_GET["end_day"])."','".$start_hour."','".$start_minute."','".$end_hour."','".$end_minute."')";
if($db->exec($insert)){
    $db->close();
    unset($db);
    echo "Insert erfolgreich";
}else{
    $db->close();
    unset($db);
    echo "Nicht wirklich...";
}

Answer 1

Fairly sure that the type of your columns is set to an integer (or any other number type) instead of TEXT.

Make sure to double check the column data type and actually dump the table for us to check if it's really set to TEXT.