how does the mysqli results get passed?

[byte1bit]

hi ppl. i'm doing a tutorial from PHP Object-Oriented Solutions, a david powers book ( http://www.amazon.com/PHP-Object-Oriented-Solutions-David-Powers/dp/1430210117/ref=sr_1_3?ie=UTF8&s=books&qid=1261679189&sr=8-3 )

in pg 296 there is a method to connect to mysqli, in class Pos_MysqlOriginalConnection:

PHP Code:

    public function getResultSet($sql) {
      $results = new Pos_MysqlOriginalResult($sql, $this->_connection);
      return $results;
    } 


the class Pos_MysqlOriginalResult() has the following definition:

PHP Code:

    public function __construct($sql, $connection) {
        if (!$this->_result = mysql_query($sql, $connection)) {
            throw new Exception(mysql_error($connection) . '. The actual query submitted was: ' . $sql);
        }
    } 


this class works, and i get the results, with all the tables. what troubles me is that i don't understand why, because they become stored in "this->_result", inside Pos_MysqlOriginalResult(), and i don't see how the property $results gets that data.

if i could inderstand that, i could extend the class Pos_MysqlOriginalResult, to perform several database related operations. Can anyone shed some light into this, please?

[byte1bit]

maybe it's overkill, but here is the original code:

ResultadosSQL:

PHP Code:

<?php 
include_once("autoload.php");

class ResultadosSQL implements Iterator, Countable {
    protected $_current; // Stores value of current element.
    protected $_key; // Stores current element key.
    protected $_valid; // Determines whether a current element exists.
    protected $_result; // Stores the database result.
    
    /**
     * Uses a MySQLi connection to submit a query and stores the result in the _result property.
     * 
     * @param object $sql         query sql
     * @param object $connection  ligação a BD
     * @return void
     */
    public function __construct($sql, $connection) {
        if (!$this->_result = $connection->query($sql)) {
            throw new RuntimeException($connection->error.'. The actual query submitted was: '.$sql);
        }
    }
    // Gets next row from database result and increments key.
    public function next() {
        $this-> _current = $this->_result->fetch_assoc();
        $this-> _valid = is_null($this->_current) ? false : true;
        $this-> _key++;
    }
    
    // Returns value of current element.
    public function current() {
        return $this->_current;
    }
    
    //Returns key of current element.
    public function key() {
        return $this-> _key;
    }
    
    // Determines whether there is current element.
    public function valid() {
        return $this->_valid;
    }
    
    //Moves to first row of database result.
    public function rewind() {
        if (!is_null($this->_key)) {
            $this->_result->data_seek(0);
        }
        $this->_key = 0;
        $this->_current = $this->_result->fetch_assoc();
        $this->_valid = is_null($this->_current) ? false : true;
    }
    
    //Returns number of rows in database result.
    public function count() {
        return $this->_result->num_rows;
    }
}

LigacaoSql:

PHP Code:

<?php 
include_once("autoload.php");
/** 
* criar 1a ligação mysqli
* 
* @author lsag
* @access public  
* @example teste.php
*/ 
class LigacaoSql {
    /**
     * MySQLi connection
     *
     * @var mysqli  Database connection using MySQL Improved.
     * @access public $_connection
     */
    protected $_connection;
    
    /**
     * Creates a database connection using MySQL Improved.
     *
     * @param string $host  Database server name.
     * @param string $user  Database user account.
     * @param string $pwd   User account password.
     * @param string $db    Name of database to connect to. */
    public function __construct ($host, $user, $pwd, $db) {
        $this->_connection = @ new mysqli ($host, $user, $pwd, $db);
        if (mysqli_connect_errno ()) {
            throw new RuntimeException ('Cannot access database: '.mysqli_connect_error ());
        }
    }
    /**
     * Submits query to database and returns result as Pos_MysqlImprovedResult object.
     *
     * @param string $sql               SQL query.
     * @return ResultadosSQL  Result of query. */
    public function getResultSet ($sql) {
        $results = new ResultadosSQL ($sql, $this->_connection);
        return $results;
    }
    
    //  Closes the database connection when object is destroyed.
    public function __destruct () {
        $this->_connection->close ();
    }
}

usage example:

PHP Code:

$conn = new LigacaoSql ('localhost', 'movimento', 'xampp', 'mar');
$result = $conn->getResultSet ('SELECT id, titulo, local, data, bandas  FROM locais'); 


[byte1bit]

well, i guess i'll just put all mysql related stuff in a single class. at least i can reuse the same connection.

[dominicdinada]

misread the question

[dominicdinada]

While it doesnt specify I am pretty sure that he is using the Code Igniter Framework in conjunction with the book if so, There are built in Database commands for basic commands. ../system/database/
The other folder to look at would be in the application folder