PHP PDO类

<?php ?//数据库连接类，不建议直接使用DB，而是对DB封装一层 ?//这个类不会被污染，不会被直接调用 ?class DB { ?????//pdo对象 ?????private $_pdo = null; ?????//用于存放实例化的对象 ?????static private $_instance = null; ???????????//公共静态方法获取实例化的对象 ?????static protected function getInstance() { ?????????if (!(self::$_instance instanceof self)) { ?????????????self::$_instance = new self(); ?????????} ?????????return self::$_instance; ?????} ???????????//私有克隆 ?????private function __clone() {} ???????????//私有构造 ?????private function __construct() { ?????????try { ?????????????$this->_pdo = new PDO(DB_DNS, DB_USER, DB_PASS, array(PDO::MYSQL_ATTR_INIT_COMMAND=>‘SET NAMES ‘.DB_CHARSET)); ?????????????$this->_pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); ?????????} catch (PDOException $e) { ?????????????exit($e->getMessage()); ?????????} ?????} ???????????//新增 ?????protected function add($_tables, Array $_addData) { ?????????$_addFields = array(); ?????????$_addValues = array(); ?????????foreach ($_addData as $_key=>$_value) { ?????????????$_addFields[] = $_key; ?????????????$_addValues[] = $_value; ?????????} ?????????$_addFields = implode(‘,‘, $_addFields); ?????????$_addValues = implode("‘,‘", $_addValues); ?????????$_sql = "INSERT INTO $_tables[0] ($_addFields) VALUES (‘$_addValues‘)"; ?????????return $this->execute($_sql)->rowCount(); ?????} ???????????//修改 ?????protected function update($_tables, Array $_param, Array $_updateData) { ?????????$_where = $_setData = ‘‘; ?????????foreach ($_param as $_key=>$_value) { ?????????????$_where .= $_value.‘ AND ‘; ?????????} ?????????$_where = ‘WHERE ‘.substr($_where, 0, -4); ?????????foreach ($_updateData as $_key=>$_value) { ?????????????if (Validate::isArray($_value)) { ?????????????????$_setData .= "$_key=$_value[0],"; ?????????????} else { ?????????????????$_setData .= "$_key=‘$_value‘,"; ?????????????} ?????????} ?????????$_setData = substr($_setData, 0, -1); ?????????$_sql = "UPDATE $_tables[0] SET $_setData $_where"; ?????????return $this->execute($_sql)->rowCount(); ?????} ???????????//验证一条数据 ?????protected function isOne($_tables, Array $_param) { ?????????$_where = ‘‘; ?????????foreach ($_param as $_key=>$_value) { ?????????????$_where .=$_value.‘ AND ‘; ?????????} ?????????$_where = ‘WHERE ‘.substr($_where, 0, -4); ?????????$_sql = "SELECT id FROM $_tables[0] $_where LIMIT 1"; ?????????return $this->execute($_sql)->rowCount(); ?????} ???????????//删除 ?????protected function delete($_tables, Array $_param) { ?????????$_where = ‘‘; ?????????foreach ($_param as $_key=>$_value) { ?????????????$_where .= $_value.‘ AND ‘; ?????????} ?????????$_where = ‘WHERE ‘.substr($_where, 0, -4); ?????????$_sql = "DELETE FROM $_tables[0] $_where LIMIT 1"; ?????????return $this->execute($_sql)->rowCount(); ?????} ???????????//查询 ?????protected function select($_tables, Array $_fileld, Array $_param = array()) { ?????????$_limit = $_order = $_where = $_like = ‘‘; ?????????if (Validate::isArray($_param) && !Validate::isNullArray($_param)) { ?????????????$_limit = isset($_param[‘limit‘]) ? ‘LIMIT ‘.$_param[‘limit‘] : ‘‘; ?????????????$_order = isset($_param[‘order‘]) ? ‘ORDER BY ‘.$_param[‘order‘] : ‘‘; ?????????????if (isset($_param[‘where‘])) { ?????????????????foreach ($_param[‘where‘] as $_key=>$_value) { ?????????????????????$_where .= $_value.‘ AND ‘; ?????????????????} ?????????????????$_where = ‘WHERE ‘.substr($_where, 0, -4); ?????????????} ?????????????if (isset($_param[‘like‘])) { ?????????????????foreach ($_param[‘like‘] as $_key=>$_value) { ?????????????????????$_like = "WHERE $_key LIKE ‘%$_value%‘"; ?????????????????} ?????????????} ?????????} ?????????$_selectFields = implode(‘,‘, $_fileld); ?????????$_table = isset($_tables[1]) ? $_tables[0].‘,‘.$_tables[1] : $_tables[0]; ?????????$_sql = "SELECT $_selectFields FROM $_table $_where $_like $_order $_limit"; ?????????$_stmt = $this->execute($_sql); ?????????$_result = array(); ?????????while (!!$_objs = $_stmt->fetchObject()) { ?????????????$_result[] = $_objs; ?????????} ?????????return Tool::setHtmlString($_result); ?????} ???????????//总记录 ?????protected function total($_tables, Array $_param = array()) { ?????????$_where = ‘‘; ?????????if (isset($_param[‘where‘])) { ?????????????foreach ($_param[‘where‘] as $_key=>$_value) { ?????????????????$_where .= $_value.‘ AND ‘; ?????????????} ?????????????$_where = ‘WHERE ‘.substr($_where, 0, -4); ?????????} ?????????$_sql = "SELECT COUNT(*) as count FROM $_tables[0] $_where"; ?????????$_stmt = $this->execute($_sql); ?????????return $_stmt->fetchObject()->count; ?????} ???????????//得到下一个ID ?????protected function nextId($_tables) { ?????????$_sql = "SHOW TABLE STATUS LIKE ‘$_tables[0]‘"; ?????????$_stmt = $this->execute($_sql); ?????????return $_stmt->fetchObject()->Auto_increment; ?????} ?????????//执行SQL ?????private function execute($_sql) { ?????????try { ?????????????$_stmt = $this->_pdo->prepare($_sql); ?????????????$_stmt->execute(); ?????????} catch (PDOException ?$e) { ?????????????exit(‘SQL语句：‘.$_sql.‘<br />错误信息：‘.$e->getMessage()); ?????????} ?????????return $_stmt; ?????} ?} ??> ?