我正在开发PHP OOP应用程序，我需要帮助。我正在开发一个具有函数db_connect的类（fetch_assoc）。它只是连接到数据库。然后我有getRows()函数从数据库中提取行然后返回它。这是代码：
function __construct() {
mysql_connect("localhost","root","") or die(mysql_error());
mysql_select_db("TestProject") or die(mysql_error());
}
function getRows() {
$sql = "SELECT * FROM Record";
$this->arr2 = $this->queryString($sql);
//Declaring that $return is an array
$return = array();
foreach ($this->arr2 as $key=>$value) {
$return[$key] = $value;
}//foreach ends here
return $return;
}
function queryString($sql) {
$query = mysql_query($sql);
$row = mysql_fetch_assoc($query);
return $row;
}// function queryString ends here()
然后在另一页上，我使用下面的代码从返回的对象中取出所有内容并显示它......但我不明白哪里出错了！
$class = new fetch_assoc;
$results = $class->getRows();
//echo out everything
foreach ($results as $result) {
foreach ($result as $key=>$value) {
echo "hello"; echo $key . ": " . $value;
}//foreach ($result as $key=>$value) ends here
答案 0 :(得分：2)
$ this-＆gt; host = $ db_config ['host'];
我在$ this-＆gt; 主机或$ db_config ['主机']
完成localhost答案 1 :(得分：0)
您的类从表中获取单行并将该数组存储在该对象上，然后返回该对象。但是，您的代码假定返回了多行。
答案 2 :(得分：0)
这是一个可以帮助您解决问题的快速示例。假设我想从 “customers” 表格中获取所有 “客户” 数据的数组，我将如何成功完成此任务？
对于这个例子，我将使用两个文件：
db.class.php
<?php
class DB {
private $host;
private $user;
private $pw;
private $db;
public function __construct($db_config) {
$this->host = $db_config['host'];
$this->user = $db_config['user'];
$this->pw = $db_config['pw'];
$this->db = $db_config['db'];
}
public function open()
{
/* establish link */
$link = new mysqli($this->host, $this->user, $this->pw, $this->db);
if (!$link) {
return false;
}
$link->autocommit(TRUE);
return $link;
}
public function getRows($table) {
/* establish database connection */
$db = self::open();
/* execute query */
$result = $db->query("SELECT * FROM $table");
/* fetch rows */
while ($row = $result->fetch_array()) {
$rows[] = $row;
}
return $rows;
}
}
<强>的init.php
<?php
require 'db.class.php';
/* database config */
$db_config = array(
'host' => '',
'user' => '',
'pw' => '',
'db' => ''
);
/* input table */
$table = 'cust';
$db = new DB($db_config);
$rows = $db->getRows($table);
foreach ($rows as $key => $value) {
echo 'Row: '.$key." : ".$value."<br />";
}
?>
答案 3 :(得分：-1)
class db_mysql
{
/**
* Class instance
*
* @var object
*/
private static $instance;
/**
* Connection to MySQL.
*
* @var string
*/
protected $link;
/**
* Holds the most recent connection.
*
* @var string
*/
protected $recent_link = null;
/**
* Holds the contents of the most recent SQL query.
*
* @var string
*/
protected $sql = '';
/**
* Holds the number of queries executed.
*
* @var integer
*/
public $query_count = 0;
/**
* The text of the most recent database error message.
*
* @var string
*/
protected $error = '';
/**
* The error number of the most recent database error message.
*
* @var integer
*/
protected $errno = '';
/**
* Do we currently have a lock in place?
*
* @var boolean
*/
protected $is_locked = false;
/**
* Show errors? If set to true, the error message/sql is displayed.
*
* @var boolean
*/
public $show_errors = false;
/**
* Database host
*
* @var string
*/
protected static $db_host;
/**
* Database username
*
* @var string
*/
protected static $db_user;
/**
* Database password
*
* @var string
*/
protected static $db_pass;
/**
* Database name.
*
* @var string
*/
protected static $db_name;
/**
* Constructor. Initializes a database connection and selects our database.
*
* private, cannot be accessed directly outside of this class
*
* @param string $db_host Database host
* @param string $db_user Database username
* @param string $db_pass Database password
* @param string $db_name Database name
* @return boolean Connection resource, if database connection is established.
*/
private function __construct()
{
self::set_params();
$this->link = @mysql_connect(self::$db_host, self::$db_user, self::$db_pass);
if (is_resource($this->link) AND @mysql_select_db(self::$db_name, $this->link))
{
$this->recent_link =& $this->link;
return $this->link;
}
else
{
// If we couldn't connect or select the db...
$this->raise_error('db_mysql::__construct() - Could not select and/or connect to database: ' . self::$db_name);
}
}
/**
* Creates an instance of the class.
*
* @param void
* @return object
*/
public static function getInstance()
{
if (!self::$instance)
{
self::$instance = new self();
}
return self::$instance;
}
/**
* Sets connection/database parameters.
*
* @param void
* @return void
*/
protected static function set_params()
{
global $dbconfig;
self::$db_host = $dbconfig['host'];
self::$db_user = $dbconfig['user'];
self::$db_pass = $dbconfig['pass'];
self::$db_name = $dbconfig['name'];
}
/**
* Executes a sql query. If optional $only_first is set to true, it will
* return the first row of the result as an array.
*
* @param string Query to run
* @param bool Return only the first row, as an array?
* @return mixed
*/
public function query($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 $result;
}
/**
* Fetches a row from a query result and returns the values from that row as an array.
*
* @param string The query result we are dealing with.
* @return array
*/
public function fetch_array($result)
{
return @mysql_fetch_assoc($result);
}
/**
* Will fetch all records from the database, and will optionally return the
* value of a single field from all records.
*
* @param string $sql SQL Query string
* @param string $field Field/column
* @return array Will return array of all db records.
*/
public function fetch_all($sql, $field = '')
{
$return = array();
if (($result = $this->query($sql)))
{
while ($row = $this->fetch_array($result))
{
$return[] = ($field) ? $row[$field] : $row;
}
$this->free_result($result);
}
return $return;
}
/**
* Returns the number of rows in a result set.
*
* @param string The query result we are dealing with.
* @return integer
*/
public function num_rows($result)
{
return @mysql_num_rows($result);
}
/**
* Retuns the number of rows affected by the most recent query
*
* @return integer
*/
public function affected_rows()
{
return @mysql_affected_rows($this->recent_link);
}
/**
* Returns the number of queries executed.
*
* @param none
* @return integer
*/
public function num_queries()
{
return $this->query_count;
}
/**
* Lock database tables
*
* @param array Array of table => lock type
* @return void
*/
public function lock($tables)
{
if (is_array($tables) AND count($tables))
{
$sql = '';
foreach ($tables AS $name => $type)
{
$sql .= (!empty($sql) ? ', ' : '') . "$name $type";
}
$this->query("LOCK TABLES $sql");
$this->is_locked = true;
}
}
/**
* Unlock tables
*/
public function unlock()
{
if ($this->is_locked)
{
$this->query("UNLOCK TABLES");
$this->is_locked = false;
}
}
/**
* Returns the ID of the most recently inserted item in an auto_increment field
*
* @return integer
*/
public function insert_id()
{
return @mysql_insert_id($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
*/
public function prepare($value, $do_like = false)
{
$value = stripslashes($value);
if ($do_like)
{
$value = str_replace(array('%', '_'), array('\%', '\_'), $value);
}
return mysql_real_escape_string($value, $this->link);
}
/**
* Frees memory associated with a query result.
*
* @param string The query result we are dealing with.
* @return boolean
*/
public function free_result($result)
{
return @mysql_free_result($result);
}
/**
* Turns database error reporting on
*/
public function show_errors()
{
$this->show_errors = true;
}
/**
* Turns database error reporting off
*/
public function hide_errors()
{
$this->show_errors = false;
}
/**
* Closes our connection to MySQL.
*
* @param none
* @return boolean
*/
public function close()
{
$this->sql = '';
return @mysql_close($this->link);
}
/**
* Returns the MySQL error message.
*
* @param none
* @return string
*/
public 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 $this->errno;
}
/**
* Gets the url/path of where we are when a MySQL error occurs.
*
* @access private
* @param none
* @return string
*/
protected function get_error_path()
{
if ($_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 $this->sql.
* @return string
*/
public function raise_error($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) . ';' : '');
}
$message = htmlspecialchars("$error_message\n\nMySQL Error: {$this->error}\nError #: {$this->errno}\nFilename: " . $this->get_error_path());
$message = '<code>' . nl2br($message) . '</code>';
if (!$this->show_errors)
{
$message = "<!--\n\n$message\n\n-->";
}
die("There seems to have been a slight problem with our database, please try again later.<br /><br />\n$message");
}
}
这是一个我以前写过的安全类很久以前很容易使用它肯定是一个例子
$dbconfig = array(
'host' => SERVER,
'user' => USER,
'pass' => PASSWORD,
'name' => DBNAME
);
$db = db_mysql::getInstance();
$getmaxcategories = $db->query("SELECT * FROM categories");
if($db->num_rows($getmaxcategories) != "0")
{
while($row = $db->fetch_array($getmaxcategories))
{
//do something
}
}
你可以使用foreach for loop或其他什么