PHP數據庫基於PDO操做類(mysql)

這是網上找的關於Mysql的操做類,很是適合初學者使用php

<?php

class Mysql {

        protected static $_dbh = null; //靜態屬性,全部數據庫實例共用,避免重複鏈接數據庫
        protected $_dbType = 'mysql';
        protected $_pconnect = true; //是否使用長鏈接
        protected $_host = 'localhost';
        protected $_port = 3306;
        protected $_user = 'root';
        protected $_pass = '';
        protected $_dbName = null; //數據庫名
        protected $_sql = false; //最後一條sql語句
        protected $_where = '';
        protected $_order = '';
        protected $_limit = '';
        protected $_field = '*';
        protected $_clear = 0; //狀態,0表示查詢條件乾淨,1表示查詢條件污染
        protected $_trans = 0; //事務指令數 

        /**
         * 初始化類
         * @param array $conf 數據庫配置
         */
        public function __construct(array $conf) {
            class_exists('PDO') or die("PDO: class not exists.");
            $this->_host = $conf['host'];
            $this->_port = $conf['port'];
            $this->_user = $conf['user'];
            $this->_pass = $conf['password'];
            $this->_dbName = $conf['dbname'];
            //鏈接數據庫
            if ( is_null(self::$_dbh) ) {
                $this->_connect();
            }
        }

        /**
         * 鏈接數據庫的方法
         */
        protected function _connect() {
            $dsn = $this->_dbType.':host='.$this->_host.';port='.$this->_port.';dbname='.$this->_dbName;
            //持久化鏈接
            $options = $this->_pconnect ? array(PDO::ATTR_PERSISTENT=>true) : array();
            try { 
                $dbh = new PDO($dsn, $this->_user, $this->_pass, $options);
                $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  //設置若是sql語句執行錯誤則拋出異常,事務會自動回滾
                $dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); //禁用prepared statements的仿真效果(防SQL注入)
            } catch (PDOException $e) { 
                die('Connection failed: ' . $e->getMessage());
            }
            $dbh->exec('SET NAMES utf8');
            self::$_dbh = $dbh;
        }

        /** 
        * 字段和表名添加 `符號
        * 保證指令中使用關鍵字不出錯 針對mysql 
        * @param string $value 
        * @return string 
        */
        protected function _addChar($value) { 
            if ('*'==$value || false!==strpos($value,'(') || false!==strpos($value,'.') || false!==strpos($value,'`')) { 
                //若是包含* 或者 使用了sql方法 則不做處理 
            } elseif (false === strpos($value,'`') ) { 
                $value = '`'.trim($value).'`';
            } 
            return $value; 
        }

        /** 
        * 取得數據表的字段信息 
        * @param string $tbName 表名
        * @return array 
        */
        protected function _tbFields($tbName) {
            $sql = 'SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME="'.$tbName.'" AND TABLE_SCHEMA="'.$this->_dbName.'"';
            $stmt = self::$_dbh->prepare($sql);
            $stmt->execute();
            $result = $stmt->fetchAll(PDO::FETCH_ASSOC);
            $ret = array();
            foreach ($result as $key=>$value) {
                $ret[$value['COLUMN_NAME']] = 1;
            }
            return $ret;
        }

        /** 
        * 過濾並格式化數據表字段
        * @param string $tbName 數據表名 
        * @param array $data POST提交數據 
        * @return array $newdata 
        */
        protected function _dataFormat($tbName,$data) {
            if (!is_array($data)) return array();
            $table_column = $this->_tbFields($tbName);
            $ret=array();
            foreach ($data as $key=>$val) {
                if (!is_scalar($val)) continue; //值不是標量則跳過
                if (array_key_exists($key,$table_column)) {
                    $key = $this->_addChar($key);
                    if (is_int($val)) { 
                        $val = intval($val); 
                    } elseif (is_float($val)) { 
                        $val = floatval($val); 
                    } elseif (preg_match('/^\(\w*(\+|\-|\*|\/)?\w*\)$/i', $val)) {
                        // 支持在字段的值裏面直接使用其它字段 ,例如 (score+1) (name) 必須包含括號
                        $val = $val;
                    } elseif (is_string($val)) { 
                        //將字符串中的單引號(')、雙引號(")、反斜線(\)與 NUL(NULL 字符轉義
                        $val = '"'.addslashes($val).'"';
                    }
                    $ret[$key] = $val;
                }
            }
            return $ret;
        }

        /**
        * 執行查詢 主要針對 SELECT, SHOW 等指令
        * @param string $sql sql指令 
        * @return mixed 
        */
        protected function _doQuery($sql='') {
            $this->_sql = $sql;
            $pdostmt = self::$_dbh->prepare($this->_sql); //prepare或者query 返回一個PDOStatement
            $pdostmt->execute();
            $result = $pdostmt->fetchAll(PDO::FETCH_ASSOC);
            return $result;
        }

        /** 
        * 執行語句 針對 INSERT, UPDATE 以及DELETE,exec結果返回受影響的行數
        * @param string $sql sql指令 
        * @return integer 
        */
        protected function _doExec($sql='') {
            $this->_sql = $sql;
            return self::$_dbh->exec($this->_sql);
        }

        /** 
        * 執行sql語句,自動判斷進行查詢或者執行操做 
        * @param string $sql SQL指令 
        * @return mixed 
        */
        public function doSql($sql='') {
            $queryIps = 'INSERT|UPDATE|DELETE|REPLACE|CREATE|DROP|LOAD DATA|SELECT .* INTO|COPY|ALTER|GRANT|REVOKE|LOCK|UNLOCK'; 
            if (preg_match('/^\s*"?(' . $queryIps . ')\s+/i', $sql)) { 
                return $this->_doExec($sql);
            }
            else {
                //查詢操做
                return $this->_doQuery($sql);
            }
        }

        /** 
        * 獲取最近一次查詢的sql語句 
        * @return String 執行的SQL 
        */
        public function getLastSql() { 
            return $this->_sql;
        }

        /**
         * 插入方法
         * @param string $tbName 操做的數據表名
         * @param array $data 字段-值的一維數組
         * @return int 受影響的行數
         */
        public function insert($tbName,array $data){
            $data = $this->_dataFormat($tbName,$data);
            if (!$data) return;
            $sql = "insert into ".$tbName."(".implode(',',array_keys($data)).") values(".implode(',',array_values($data)).")";
            return $this->_doExec($sql);
        }

        /**
         * 刪除方法
         * @param string $tbName 操做的數據表名
         * @return int 受影響的行數
         */
        public function delete($tbName) {
            //安全考慮,阻止全表刪除
            if (!trim($this->_where)) return false;
            $sql = "delete from ".$tbName." ".$this->_where;
            $this->_clear = 1;
            $this->_clear();
            return $this->_doExec($sql);
        }

        /**
         * 更新函數
         * @param string $tbName 操做的數據表名
         * @param array $data 參數數組
         * @return int 受影響的行數
         */
        public function update($tbName,array $data) {
            //安全考慮,阻止全表更新
            if (!trim($this->_where)) return false;
            $data = $this->_dataFormat($tbName,$data);
            if (!$data) return;
            $valArr = '';
            foreach($data as $k=>$v){
                $valArr[] = $k.'='.$v;
            }
            $valStr = implode(',', $valArr);
            $sql = "update ".trim($tbName)." set ".trim($valStr)." ".trim($this->_where);
            return $this->_doExec($sql);
        }

        /**
         * 查詢函數
         * @param string $tbName 操做的數據表名
         * @return array 結果集
         */
        public function select($tbName='') {
            $sql = "select ".trim($this->_field)." from ".$tbName." ".trim($this->_where)." ".trim($this->_order)." ".trim($this->_limit);
            //echo $sql;
            $this->_clear = 1;
            $this->_clear();
            return $this->_doQuery(trim($sql));
        }

        /**
         * @param mixed $option 組合條件的二維數組,例:$option['field1'] = array(1,'=>','or')
         * @return $this
         */
        public function where($option) {
            if ($this->_clear>0) $this->_clear();
            $this->_where = ' where ';
            $logic = 'and';
            if (is_string($option)) {
                $this->_where .= $option;
            }
            elseif (is_array($option)) {
                foreach($option as $k=>$v) {
                    if (is_array($v)) {
                        $relative = isset($v[1]) ? $v[1] : '=';
                        $logic    = isset($v[2]) ? $v[2] : 'and';
                        $condition = ' ('.$this->_addChar($k).' '.$relative.' '.$v[0].') ';
                    }
                    else {
                        $logic = 'and';
                        $condition = ' ('.$this->_addChar($k).'='.$v.') ';
                    }
                    $this->_where .= isset($mark) ? $logic.$condition : $condition;
                    $mark = 1;
                }
            }
            return $this;
        }

        /**
         * 設置排序
         * @param mixed $option 排序條件數組 例:array('sort'=>'desc')
         * @return $this
         */
        public function order($option) {
            if ($this->_clear>0) $this->_clear();
            $this->_order = ' order by ';
            if (is_string($option)) {
                $this->_order .= $option;
            }
            elseif (is_array($option)) {
                foreach($option as $k=>$v){
                    $order = $this->_addChar($k).' '.$v;
                    $this->_order .= isset($mark) ? ','.$order : $order;
                    $mark = 1;
                }
            }
            return $this;
        }

        /**
         * 設置查詢行數及頁數
         * @param int $page pageSize不爲空時爲頁數,不然爲行數
         * @param int $pageSize 爲空則函數設定取出行數,不爲空則設定取出行數及頁數
         * @return $this
         */
        public function limit($page,$pageSize=null) {
            if ($this->_clear>0) $this->_clear();
            if ($pageSize===null) {
                $this->_limit = "limit ".$page;
            }
            else {
                $pageval = intval( ($page - 1) * $pageSize);
                $this->_limit = "limit ".$pageval.",".$pageSize;
            }
            return $this;
        }

        /**
         * 設置查詢字段
         * @param mixed $field 字段數組
         * @return $this
         */
        public function field($field){
            if ($this->_clear>0) $this->_clear();
            if (is_string($field)) {
                $field = explode(',', $field);
            }
            $nField = array_map(array($this,'_addChar'), $field);
            $this->_field = implode(',', $nField);
            return $this;
        }

        /**
         * 清理標記函數
         */
        protected function _clear() {
            $this->_where = '';
            $this->_order = '';
            $this->_limit = '';
            $this->_field = '*';
            $this->_clear = 0;
        }

        /**
         * 手動清理標記
         * @return $this
         */
        public function clearKey() {
            $this->_clear();
            return $this;
        }

        /**
        * 啓動事務 
        * @return void 
        */
        public function startTrans() { 
            //數據rollback 支持 
            if ($this->_trans==0) self::$_dbh->beginTransaction();
            $this->_trans++; 
            return; 
        }

        /** 
        * 用於非自動提交狀態下面的查詢提交 
        * @return boolen 
        */
        public function commit() {
            $result = true;
            if ($this->_trans>0) { 
                $result = self::$_dbh->commit(); 
                $this->_trans = 0;
            } 
            return $result;
        }

        /** 
        * 事務回滾 
        * @return boolen 
        */
        public function rollback() {
            $result = true;
            if ($this->_trans>0) {
                $result = self::$_dbh->rollback();
                $this->_trans = 0;
            }
            return $result;
        }

        /**
        * 關閉鏈接
        * PHP 在腳本結束時會自動關閉鏈接。
        */
        public function close() {
            if (!is_null(self::$_dbh)) self::$_dbh = null;
        }

}
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