读写分离MYSQL类

2014年4月27日 12:34:08

概述:

1. 根据sql语句判断是连接读库还是写库

2. 链式调用$this->where()->get()

3. 不同的主机对应不同的实例, 不再多次new

 <?php
 class DBRWmysql
 {
     private static $Instance = null;

     private $links = array();//链接数组
     private $link = null; //当前连接
     public $dbType = 'read';

     public $_host=''; //数据库所在主机名
     public $_database = '';//当前数据库名
     public $_tablename = '';//当前表的表名
     public $_dt ='';//database.tablename
     public $isRelease = 0; //查询完成后是否释放

     public $fields = '*';
     public $arrWhere = [];
     public $order = '';
     public $arrOrder = [];
     public $limit = '';
     public $sql = '';

     public $rs;//结果集

     private function __construct($database='', $tablename='', $isRelease=0)
     {
         $this->_database = $database;//database name
         $this->_tablename = $tablename;//table name
         $this->_dt = "`{$this->_database}`.`{$this->_tablename}`";
         $this->isRelease = $isRelease;
     }

     public static function getInstance($database='', $tablename='', $isRelease=0)
     {
         if (self::$Instance == null) {
             self::$Instance = new DBRWmysql($database, $tablename, $isRelease);
         }

         self::$Instance->_database  = $database;
         self::$Instance->_tablename = $tablename;
         self::$Instance->_dt        = "`{$database}`.`{$tablename}`";
         self::$Instance->isRelease  = $isRelease;

         return self::$Instance;
     }

     //如果主机没变,并且已经存在MYSQL连接,就不再创建新的连接
     //如果主机改变,就再生成一个实例创建一个连接
     //type == 'write'或'read'
     public function getLink($type)
     {
         $this->dbType = $$type;

         //随机选取一个数据库连接(区分读写)
         $dbConfig = DBConfig::$$type;
         $randKey = array_rand($dbConfig);
         $config = $dbConfig[$randKey];

         //链接数据库
         $host = $config['host'];
         $username = $config['username'];
         $password = $config['password'];

         if (empty($this->links[$host])) {
             $this->_host = $host;
             $this->links[$host] = new mysqli($host, $username, $password);
             if($this->links[$host]->connect_error) {
                 $this->error($this->links[$host]->connect_error);
             }
         }

         //初始化链接
         $this->link = $this->links[$host];
         $this->link->query("set names utf8mb4;"); //支持emoji表情
         $this->link->query("use {$this->_database};");
     }

     public function getCurrentLinks()
     {
         return $this->links;
     }

     //析构函数
     public function __destruct()
     {
         foreach ($this->links as $v) {
             $v->close();
         }
     }

     //查询封装
     public function query($sql)
     {
         $this->sql = $sql;
         if (strpos($sql, 'select') !== false) {
             $this->getLink('read');//读库
         } else {
             $this->getLink('write');//写库
         }

         $this->rs = $this->link->query($sql);
         ($this->rs === false) && $this->error('sql error: '.$sql.PHP_EOL.$this->link->error);

         //查询完成后释放链接, 并删除链接对象
         if ($this->isRelease) {
             $this->link->close();
             unset($this->links[$this->_host]);
         }
         return $this->rs;
     }

     //增
     public function insert($arrData)
     {
         foreach ($arrData as $key=>$value) {
             $fields[] = $key;
             $values[] = "'".$value."'";
             // $fields[] = '`'.$key.'`';
             // $values[] = "'".$value."'";
         }
         $strFields = implode(',', $fields);
         $strValues = implode(',', $values);
         $sql = "insert into {$this->_dt} ($strFields) values ($strValues)";
         $this->query($sql);
         $insert_id = $this->link->insert_id;

         return $insert_id;
     }

     //增
     public function replace($arrData)
     {
         foreach ($arrData as $key=>$value) {
             $fields[] = $key;
             $values[] = "'{$value}'";
         }
         $strFields = implode(',', $fields);
         $strValues = implode(',', $values);
         $sql = "replace into {$this->_dt} ($strFields) values ($strValues)";

         $this->query($sql);

         return $this->link->insert_id;
     }

     //增
     //每次插入多条记录
     //每条记录的字段相同,但是值不一样
     public function insertm($arrFields, $arrData)
     {
         foreach ($arrFields as $v) {
             // $fields[] = "`{$v}`";
             $fields[] = $v;
         }

         foreach ($arrData as $v) {
             $data[] = '('.implode(',', $v).')';
         }

         $strFields = implode(',', $fields);
         $strData = implode(',', $data);

         $sql = "insert into {$this->_dt} ($strFields) values {$strData}";

         $this->query($sql);

         return $this->link->insert_id;
     }

     //删
     public function delete()
     {
         $where = $this->getWhere();
         $limit = $this->getLimit();

         $sql = " delete from {$this->_dt} {$where} {$limit}";
         $this->query($sql);
         return $this->link->affected_rows;
     }

     //改
     public function update($data)
     {
         $where = $this->getWhere();

         $arrSql = array();
         foreach ($data as $key=>$value) {
             $arrSql[] = "{$key}='{$value}'";
         }
         $strSql = implode(',', $arrSql);

         $sql = "update {$this->_dt} set {$strSql} {$where} {$this->limit}";

         $this->query($sql);

         return $this->link->affected_rows;

     }

     //获取总数
     public function getCount()
     {
         $where = $this->getWhere();

         $sql = " select count(1) as n from {$this->_dt} {$where} ";
         $resault = $this->query($sql);

         ($resault===false) && $this->error('getCount error: '.$sql);

         $arrRs = $this->rsToArray($resault);

         $num = array_shift($arrRs);
         return $num['n'];
     }

     //将结果集转换成数组返回
     //如果field不为空，则返回的数组以$field为键重新索引
     public function rsToArray($field = '')
     {
         $arrRs = $this->rs->fetch_all(MYSQLI_ASSOC); //该函数只能用于php的mysqlnd驱动
         $this->rs->free();//释放结果集

         if ($field) {
             $arrResult = [];
             foreach ($arrRs as $v) {
                 $arrResult[$v[$field]] = $v;
             }
             return $arrResult;
         }

         return $arrRs;
     }

     //给字段名加上反引号
     public function qw($strFields)
     {
         $strFields = preg_replace('#\s+#', ' ', $strFields);
         $arrNewFields = explode(' ', $strFields );
         $arrNewFields = array_filter($arrNewFields);
         foreach ($arrNewFields as $k => $v) {
             $arrNewFields[$k]= '`'.$v.'`';
         }
         return implode(',', $arrNewFields);
     }

     //处理入库数据,将字符串格式的数据转换为...格式(未实现)
     public function getInsertData($strData)
     {
         // $bmap = "jingdu,$jingdu weidu,$weidu content,$content";
     }

     //select in
     //arrData 整数数组，最好是整数
     public function select_in($key, $arrData, $fields='')
     {
         $fields = $fields ? $fields : '*';
         sort($arrData);
         $len = count($arrData);
         $cur = 0;
         $pre = $arrData[0];

         $new = array('0' => array($arrData[0]));
         for ($i = 1; $i < $len; $i++) {
             if (($arrData[$i] - $pre) == 1 ) {
                 $new[$cur][] = $arrData[$i];
             } else {
                 $cur = $i;
                 $new[$cur][] = $arrData[$i];
             }
             $pre = $arrData[$i];
         }

         $arrSql = array();
         foreach ($new as $v) {
             $len = count($v) - 1;
             if ($len) {
                 $s = $v[0];
                 $e = end($v);
                 $sql = "(select $fields from {$this->_dt} where $key between $s and $e)";
             } else {
                 $s = $v[0];
                 $sql = "(select $fields from {$this->_dt} where $key = $s)";
             }

             $arrSql[] = $sql;
         }

         $strUnion = implode(' UNION ALL ', $arrSql);
         $res = $this->query($strUnion);
         return $this->rstoarray($res);
     }

     //where in
     public function setWhereIn($key, $arrData)
     {
         if (empty($arrData)) {
             $str = "(`{$key}` in ('0'))";
             $this->addWhere($str);
             return $str;
         }

         foreach ($arrData as &$v) {
             $v = "'{$v}'";
         }
         $str = implode(',', $arrData);
         $str = "(`{$key}` in ( {$str} ))";

         $this->addWhere($str);

         return $this;
     }

     //where in
     public function setWhere($arrData)
     {
         if (empty($arrData)) {
             return '';
         }

         foreach ($arrData as $k => $v) {
             $str = "(`{$k}` = '{$v}')";
             $this->addWhere($str);
         }

         return $this;
     }

     //between and
     public function setWhereBetween($key, $min, $max)
     {
         $str = "(`{$key}` between '{$min}' and '{$max}')";
         $this->addWhere($str);
         return $this;
     }

     //where a>b
     public function setWhereBT($key, $value)
     {
         $str = "(`{$key}` > '{$value}')";
         $this->addWhere($str);
         return $this;
     }

     //where a<b
     public function setWhereLT($key, $value)
     {
         $str = "(`{$key}` < '{$value}')";
         $this->addWhere($str);
         return $this;
     }

     //组装where条件
     public function addWhere($where)
     {
         $this->arrWhere[] = $where;
     }

     //获取最终查询用的where条件
     public function getWhere()
     {
         if (empty($this->arrWhere)) {
             return 'where 1';
         } else {
             return 'where '.implode(' and ', $this->arrWhere);
         }
     }

     //以逗号隔开
     public function setFields($fields)
     {
         $this->fields = $fields;
         return $this;
     }

     // order by a desc
     public function setOrder($order)
     {
         $this->arrOrder[] = $order;
         return $this;
     }

     //获取order语句
     public function getOrder()
     {
         if (empty($this->arrOrder)) {
             return '';
         } else {
             $str = implode(',', $this->arrOrder);
             $this->order = "order by {$str}";
         }
         return $this->order;
     }

     //e.g. '0, 10'
     //用limit的时候可以加where条件优化：select ... where id > 1234 limit 0, 10
     public function setLimit($limit)
     {
         $this->limit = 'limit '.$limit;
         return $this;
     }

     //直接查询sql语句, 返回数组格式
     public function arrQuery($sql, $field='')
     {
         $this->query($sql);
         $this->clearQuery();
         ($this->rs===false) && $this->error('select error: '.$sql);
         return $this->rsToArray($field);
     }

     //如果 $field 不为空, 则返回的结果以该字段的值为索引
     //暂不支持join
     public function get($field='')
     {
         $where = $this->getWhere();
         $order = $this->getOrder();

         $sql = " select {$this->fields} from {$this->_dt} {$where} {$order} {$this->limit} ";
         return $this->arrQuery($sql, $field);
     }

     //获取一条记录
     public function getOne()
     {
         $this->setLimit(1);
         $rs = $this->get();

         return !empty($rs) ? $rs[0] : [];
     }

     //获取一条记录的某一个字段的值
     public function getOneField($field)
     {
         $this->setFields($field);
         $rs = $this->getOne();

         return !empty($rs[$field]) ? $rs[$field] : '';
     }

     //获取数据集中所有某个字段的值
     public function getFields($field)
     {
         $this->setFields($field);
         $rs = $this->get();
         $result = [];
         foreach ($rs as $v) {
             $result[] = $v[$field];
         }
         unset($rs);

         return $result;
     }

     //清除查询条件
     //防止干扰下次查询
     public function clearQuery()
     {
         $this->fields = '*';
         $this->arrWhere = [];
         $this->order = '';
         $this->arrOrder = [];
         $this->limit = '';
     }

     //断开数据库连接
     public function close()
     {
         $this->link->close();
     }

     //事务
     //自动提交开关
     public function autocommit($bool)
     {
         $this->link->autocommit($bool);
     }

     //事务完成提交
     public function commit()
     {
         $this->link->commit();
     }

     //回滚
     public function rollback()
     {
         $this->link->rollback();
     }

     //输出错误sql语句
     public function error($sql)
     {
         //if (IS_TEST) {}
         exit($sql);
     }
 }

最后编辑: 2016年4月16日 19:45:14 星期六