PDO ::引用nulls，bools等等

Question

PDO::quote always seems to slap on two single quotes regardless of the type of value I pass it, or the parameter type I set.

e.g.,

$x = null;
echo $pdo->quote($x,PDO::PARAM_NULL); // ''

Thus I've extended the PDO class with my own function,

public function quote($value, $parameter_type=PDO::PARAM_STR) {
    if(is_null($value)) return 'NULL';
    elseif(is_bool($value)) return $value ? 'TRUE' : 'FALSE';
    elseif(is_int($value)||is_float($value)) return $value;
    return parent::quote($value, $parameter_type);
}

Have I missed any cases? Is there any harm in doing this?

Do the different parameter types ever do anything?

Answer 1

Per the documentation, the results of a call to quote() are dependent on the PDO driver, because different databases escape strings in different ways. So some drivers may require quotes in different places than others. But really, if you know you don't need quotes, then you shouldn't be calling quote().

As for your function, it depends on what you're trying to do. If you're trying to build a database-agnostic data access layer, then your function will break for some databases. This is because not all DBs have boolean types, e.g. there is no such value as TRUE in SQLite.

But really, it would be better to just use prepared statements and not touch quote() at all. Even the documentation for quote says so, after all.