<?php

/***************************************************************************
*
* Author : Eric Sizemore ( www.secondversion.com & www.phpsociety.com )
* Package : Simple MySQL DB Class
* Version : 1.0.0
* Copyright: (C) 2007 Eric Sizemore
* Site : www.secondversion.com & www.phpsociety.com
* Email : esizemore05@gmail.com
* File : mysql.class.php
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
***************************************************************************/

/**
* Class to interact with a mysql database
*/
class db_mysql
{
/**
* Connection to MySQL.
*
* @var string
*/
var $link;

/**
* Holds the most recent connection.
*
* @var string
*/
var $recent_link = null;

/**
* Holds the contents of the most recent SQL query.
*
* @var string
*/
var $sql = '';

/**
* Holds the number of queries executed.
*
* @var integer
*/
var $query_count = 0;

/**
* The text of the most recent database error message.
*
* @var string
*/
var $error = '';

/**
* The error number of the most recent database error message.
*
* @var integer
*/
var $errno = '';

/**
* Do we currently have a lock in place?
*
* @var boolean
*/
var $is_locked = false;

/**
* Show errors? If set to true, the error message/sql is displayed.
*
* @var boolean
*/
var $show_errors = false;

/**
* Constructor. Initializes a database connection and selects our database.
*
* @param string Database host
* @param string Database username
* @param string Database password
* @param string Database name
* @return boolean
*/
function db_mysql($db_host, $db_user, $db_pass, $db_name)
{
$this->link = @mysql_connect($db_host, $db_user, $db_pass);

if ($this->link)
{
if (@mysql_select_db($db_name, $this->link))
{
$this->recent_link =& $this->link;
return $this->link;
}
}
// If we couldn't connect or select the db...
$this->raise_error("Could not select and/or connect to database: $db_name");
}

/**
* Executes a sql query. If optional $only_first is set to true, it will
* return the first row of the result as an array.
*
* @param string Query to run
* @param bool Return only the first row, as an array?
* @return mixed
*/
function query($sql, $only_first = false)
{
$this->recent_link =& $this->link;
$this->sql =& $sql;
$result = @mysql_query($sql, $this->link);

$this->query_count++;

if ($only_first)
{
$return = $this->fetch_array($result);
$this->free_result($result);
return $return;
}
return $result;
}

/**
* Fetches a row from a query result and returns the values from that row as an array.
*
* @param string The query result we are dealing with.
* @return array
*/
function fetch_array($result)
{
return @mysql_fetch_assoc($result);
}

/**
* Returns the number of rows in a result set.
*
* @param string The query result we are dealing with.
* @return integer
*/
function num_rows($result)
{
return @mysql_num_rows($result);
}

/**
* Retuns the number of rows affected by the most recent query
*
* @return integer
*/
function affected_rows()
{
return @mysql_affected_rows($this->recent_link);
}

/**
* Returns the number of queries executed.
*
* @param none
* @return integer
*/
function num_queries()
{
return $this->query_count;
}

/**
* Lock database tables
*
* @param array Array of table => lock type
* @return void
*/
function lock($tables)
{
if (is_array($tables) AND count($tables))
{
$sql = '';

foreach ($tables AS $name => $type)
{
$sql .= (!empty($sql) ? ', ' : '') . "$name $type";
}

$this->query("LOCK TABLES $sql");
$this->is_locked = true;
}
}

/**
* Unlock tables
*/
function unlock()
{
if ($this->is_locked)
{
$this->query("UNLOCK TABLES");
}
}

/**
* Returns the ID of the most recently inserted item in an auto_increment field
*
* @return integer
*/
function insert_id()
{
return @mysql_insert_id($this->link);
}

/**
* Escapes a value to make it safe for using in queries.
*
* @param string Value to be escaped
* @param bool Do we need to escape this string for a LIKE statement?
* @return string
*/
function prepare($value, $do_like = false)
{
$value = stripslashes($value);

if ($do_like)
{
$value = str_replace(array('%', '_'), array('\%', '\_'), $value);
}

if (function_exists('mysql_real_escape_string'))
{
return mysql_real_escape_string($value, $this->link);
}
else
{
return mysql_escape_string($value);
}
}

/**
* Frees memory associated with a query result.
*
* @param string The query result we are dealing with.
* @return boolean
*/
function free_result($result)
{
return @mysql_free_result($result);
}

/**
* Turns database error reporting on
*/
function show_errors()
{
$this->show_errors = true;
}

/**
* Turns database error reporting off
*/
function hide_errors()
{
$this->show_errors = false;
}

/**
* Closes our connection to MySQL.
*
* @param none
* @return boolean
*/
function close()
{
$this->sql = '';
return @mysql_close($this->link);
}

/**
* Returns the MySQL error message.
*
* @param none
* @return string
*/
function error()
{
$this->error = (is_null($this->recent_link)) ? '' : mysql_error($this->recent_link);
return $this->error;
}

/**
* Returns the MySQL error number.
*
* @param none
* @return string
*/
function errno()
{
$this->errno = (is_null($this->recent_link)) ? 0 : mysql_errno($this->recent_link);
return $this->errno;
}

/**
* Gets the url/path of where we are when a MySQL error occurs.
*
* @access private
* @param none
* @return string
*/
function _get_error_path()
{
if ($_SERVER['REQUEST_URI'])
{
$errorpath = $_SERVER['REQUEST_URI'];
}
else
{
if ($_SERVER['PATH_INFO'])
{
$errorpath = $_SERVER['PATH_INFO'];
}
else
{
$errorpath = $_SERVER['PHP_SELF'];
}

if ($_SERVER['QUERY_STRING'])
{
$errorpath .= '?' . $_SERVER['QUERY_STRING'];
}
}

if (($pos = strpos($errorpath, '?')) !== false)
{
$errorpath = urldecode(substr($errorpath, 0, $pos)) . substr($errorpath, $pos);
}
else
{
$errorpath = urldecode($errorpath);
}
return $_SERVER['HTTP_HOST'] . $errorpath;
}

/**
* If there is a database error, the script will be stopped and an error message displayed.
*
* @param string The error message. If empty, one will be built with $this->sql.
* @return string
*/
function raise_error($error_message = '')
{
if ($this->recent_link)
{
$this->error = $this->error($this->recent_link);
$this->errno = $this->errno($this->recent_link);
}

if ($error_message == '')
{
$this->sql = "Error in SQL query:\n\n" . rtrim($this->sql) . ';';
$error_message =& $this->sql;
}
else
{
$error_message = $error_message . ($this->sql != '' ? "\n\nSQL:" . rtrim($this->sql) . ';' : '');
}

$message = "<textarea rows=\"10\" cols=\"80\">MySQL Error:\n\n\n$error_message\n\nError: {$this->error}\nError #: {$this->errno}\nFilename: " . $this->_get_error_path() . "\n</textarea>";

if (!$this->show_errors)
{
$message = "";
}
die("There seems to have been a slight problem with our database, please try again later.<br /><br />\n$message");
}
}

?>