public static function getInstance()
{
if (empty(self::$instance)) {
self::$instance = new self();
}
return self::$instance;
}
public static function getInstance()
{
//判断self::$instance 是否已经被实例化
if (!self::$instance instanceof self) {
self::$instance = new self();
}
return self::$instance;
}
public static function connect()
{
try {
self::$db = new \PDO('mysql:' . 'host=' . \Config::$db['host'] . ';' . 'dbname=' . \Config::$db['dbname'], \Config::$db['username'], \Config::$db['password'], [\PDO::ATTR_PERSISTENT => \Config::$db['persistent']]);
} catch (\PDOException $e) {
http_response_code(500);
exit('DB connection error: ' . $e->getMessage());
}
self::$db->query('SET time_zone = "+00:00"');
}
/**
* 单例模式，创建db
* @param object $config 配置文件
* @return object DB连接
*/
static function getDb()
{
if (!self::$_db instanceof self) {
//提取config
$config = (require_once 'Config.php');
extract($config);
self::$_db = new DB($driver, $host, $dbname, $user, $password);
}
return self::$_db;
}
public function __construct($type = null, $start = null, $offset = false, $where = 1)
{
self::$db = CoreDB::init();
if (is_null($type)) {
throw new CESyntaxError('Select type of aggregate.');
}
if (!class_exists($type)) {
throw new CETypeError('Cannot find specified type of aggregate.');
}
$this->type = $type;
$this->load($start, $offset, $where);
}
/**
* Connecting with database.
*
* Function create an singleton object, and creates database connection.
* Connection handler is stored in self::$_object->db variable.
*
* @param string $type database type. Only 'mysql' like for now.
* @return object PDO
* @throws CESyntaxError if incorrect database type
* @throws CEDBError if problem with connect with database
*
* @access public
* @static
*/
public static function init($type = 'mysql')
{
if (!isset(self::$_object)) {
try {
switch ($type) {
case 'mysql':
$dsn = sprintf('mysql:host=%s;dbname=%s', DB_HOST, DB_NAME);
self::$_object = new PDO($dsn, DB_USER, DB_PASS);
break;
default:
throw new CESyntaxError('Invalid database type.');
}
self::$_object->setAttribute(PDO::ATTR_AUTOCOMMIT, true);
self::$_object->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
self::$_object->setAttribute(PDO::ATTR_CASE, PDO::CASE_NATURAL);
self::$_object->setAttribute(PDO::ATTR_STRINGIFY_FETCHES, false);
} catch (PDOException $e) {
throw new CEDBError(sprintf('Connection failed: %s.', $e->getMessage()));
}
}
return self::$_object;
}
/**
* Constructor
*
* Creates prepared statements with acquire bindings.
*
* @access private
*/
private function __construct()
{
$this->_db = CoreDB::init();
$this->_stmt[self::ST_SEL] = $this->_db->prepare(sprintf("\n SELECT\n `value`\n FROM\n %s\n WHERE\n `key` = :key", TBL_CONFIG));
$this->_stmt[self::ST_DB] = $this->_db->prepare(sprintf("\n REPLACE\n %s\n SET\n `key` = :key,\n `value` = :value", TBL_CONFIG));
$this->_stmt[self::ST_DEL] = $this->_db->prepare(sprintf("\n DELETE FROM\n %s\n WHERE\n `key` = :key", TBL_CONFIG));
}
public static function setConfig($config)
{
self::$config = $config;
}
public static function close()
{
self::$__instance->close();
self::$__instance = NULL;
return TRUE;
}
public function &database($config = NULL, $is_return = false, $force_new_conn = false)
{
$core_db = self::$system['db'];
$db_cfg_key = $core_db['active_group'];
if (is_string($config) && !empty($config)) {
//传递配置key
$db_cfg = $core_db[$config];
} elseif (is_array($config)) {
//传递配置
$db_cfg = $config;
} else {
//没有传递配置，使用默认配置
$db_cfg = $core_db[$db_cfg_key];
}
if ($is_return) {
return CoreDB::getInstance($db_cfg, $force_new_conn);
} else {
if ($force_new_conn || !is_object($this->db) || !is_null($config)) {
$this->db = CoreDB::getInstance($db_cfg, $force_new_conn);
}
return $this->db;
}
}
public function __construct()
{
$this->db = CoreDB::connect();
}
/**
* Constructor
*
* Initialize database connection.
*/
public function __construct()
{
self::$db = CoreDB::init();
}
public final function __destruct()
{
self::$instance = null;
}
