Extend mysqli_result

问题:

I have extended PHP's mysqli class, which works fine. But how can I make it return a custom result object (or a boolean for insert/update/delete etc) when querying?

namespace MyApp;
class MySQLi extends \mysqli {
    public function query($query, $resultmode = null) {
        // This needs to return a MySQLiResult or a boolean
    }
}
class MySQLiResult extends \mysqli_result {
}

Doing this I can return a MySQLiResult object, but I can't figure out how to return a boolean for non select based queries:

public function query($query, $resultmode = null) {
    $this->real_query($query); 
    return new MySQLiResult($this);
}

Update:

This is what I ended up using:

class MySQLi extends \mysqli {

    public function query($query, $resultmode = null) {
        $result = parent::query($query, $resultmode);
        return is_bool($result) ? $result : new MySQLiResult($result);
    }

}


class MySQLiResult {

    private $result;

    public function __construct(mysqli_result $result) {
        $this->result = $result;
    }

    public function __call($name, $arguments) {
        return call_user_func_array(array($this->result, $name), $arguments);
    }

    public function __set($name, $value) {
        $this->result->$name = $value;
    }

    public function __get($name) {
        return $this->result->$name;
    }

}

回答1:

Probably the simplest thing to do would be treat your MySQLiResult class as a decorator for mysqli_result. For example

class MySQLiResult
{
    private $result;

    public function __construct(\mysqli_result $result)
    {
        $this->result = $result;
    }
}

You could then proxy method calls to the internal result and decorate (add functionality) where required.

回答2:

Phil's answer is OK, but it is possible to just extend MySQLi_Result by checking mysqli::field_count. Checkout the documentation for mysqli::field_count

This function can be useful when using the mysqli_store_result() function to determine if the query should have produced a non-empty result set or not without knowing the nature of the query.

This is just what we needed.

public MySQL extends MySQLi
{
    public function query($query)
    {
        if ($this->real_query($query)) {
            if ($this->field_count > 0) {
                return new MySQL_Result($this);
            }
            return true;
        }

        throw new MySQL_Exception($this->error, $this->errno);
    }
}

Now you can extend your result class from MySQLi_Result and implement some useful interfaces like SeekableIterator so you can use foreach on your resultset:

class MySQL_Result extends MySQLi_Result implements Countable, SeekableIterator, ArrayAccess
{
    ...
}