$model->where()->field()->limit()->select()

use PDO;
class CyDB extends PDO
{
    private $config = null;
    public $table;   //当前操作的数据表名字
    protected $fields;
    private $where = array();
    private $select = ‘*‘;
    public $sql;
    public $msg;
    private $stmt; //PDOStatement实例
    private $param = array();
    /**
     * 初始化一个数据库实例
     * @return db
     */
    public function __construct()
    {
        $this->config[‘dsn‘] = \Cy\CyConfig::getConfig(‘DataBase‘, ‘DSN‘);
        $this->config[‘user‘] = \Cy\CyConfig::getConfig(‘DataBase‘, ‘USER‘);
        $this->config[‘pass‘] = \Cy\CyConfig::getConfig(‘DataBase‘, ‘PASSWD‘);
        $this->config[‘options‘] = \Cy\CyConfig::getConfig(‘DataBase‘, ‘OPTIONS‘);
        try {
            parent::__construct($this->config[‘dsn‘], $this->config[‘user‘], $this->config[‘pass‘], $this->config[‘options‘]);
        } catch (\PDOException $e) {
            throw new \Exception(‘数据库连接失败‘ . $e->getMessage());
        }
    }
    /**
     * 重建连接
     */
    public function reConnect()
    {
        $attr = array();
        foreach ($this as $k => $v) {
            $attr[$k] = $v;
        }
        parent::__construct($this->config[‘dsn‘], $this->config[‘user‘], $this->config[‘pass‘], $this->config[‘options‘]);
        foreach ($attr as $k => $v) {
            $this->$k = $v;
        }
    }
    /**
     * 插入数据
     * @param array $data
     */
    public function insert($data = array())
    {
        $this->sql = sprintf(‘INSERT INTO `%s` SET %s‘, $this->table, implode(‘,‘, $this->joinKeyVal($data)));
        if (!$this->query($this->sql)) {
            return false;
        }
        return $this->lastInsertId();
    }
    /**
     * 插入数据，当出现key重复时更新数据
     * INSERT ... tbl_name SET ... ON DUPLICATE KEY UPDATE ...
     * @param array $insertData 不存在记录时的新增数据
     * @param array $updateData 存在记录时的更新数据
     * @return int 新增记录id
     */
    public function insertDuplicate(array $insertData, array $updateData)
    {
        $this->sql = sprintf(‘INSERT INTO %s SET %s ON DUPLICATE KEY UPDATE %s‘, $this->table,
            implode(‘,‘, $this->joinKeyVal($insertData)), implode(‘,‘, $this->joinKeyVal($updateData)));
        if (!$this->query($this->sql)) {
            return false;
        }
        return $this->lastInsertId();
    }
    /**
     * 计算有多少条记录
     */
    public function count($strCountSql = ‘count(*)‘)
    {
        $this->sql = sprintf(‘SELECT %s FROM %s %s‘, $strCountSql, $this->table, $this->condition());
        $sth = $this->query($this->sql);
        $res = $sth->fetchColumn(0);
        return (int)$res;
    }
    /**
     * @param $sql
     * @param int $type
     * @param int $returnType 1 默认（sql错误时返回空数组，没查到数据时返回false） ，2 （sql错误时返回 false，没查到数据时返回空数组）
     * @return array|bool|mixed
     */
    public function row($sql, $type = PDO::FETCH_ASSOC, $returnType = 1)
    {
        $this->sql = $sql;
        $sth = $this->query($this->sql);
        if (!$sth) {
            return $returnType == 1 ? array() : false;
        }
        $res = $sth->fetch($type);
        return ($returnType == 1 || !empty($res)) ? $res : array();
    }
    public function rows($sql, $start = 0, $size = 0, $orderBy = ‘‘, $groupBy = ‘‘, $type = PDO::FETCH_ASSOC)
    {
        $this->sql = $sql;
        if ($groupBy) {
            $this->sql = sprintf(‘%s GROUP BY %s‘, $this->sql, $groupBy);
        }
        if ($orderBy) {
            $this->sql = sprintf(‘%s ORDER BY %s‘, $this->sql, $orderBy);
        }
        if ($size > 0) {
            //$this->sql = sprintf(‘%s LIMIT %d,%d‘, $this->sql, $start, ($size>1000?1000:$size));
            $this->sql = sprintf(‘%s LIMIT %d,%d‘, $this->sql, $start, $size);
        }
        $sth = $this->query($this->sql);
        if (!$sth) {
            return array();
        }
        return $sth->fetchAll($type);
    }
    /**
     * 更新数据
     * @param array $data
     * 返回受影响的行数/出错返回false
     */
    public function update($data = array())
    {
        $this->sql = sprintf(‘UPDATE %s SET %s %s‘, $this->table, implode(‘,‘, $this->joinKeyVal($data)), $this->condition());
        return $this->exec($this->sql);
    }
    /**
     * 根据查询条件返回一条记录
     * @param int $returnType 参见 $this->row() 注释
     * @return array|mixed
     */
    public function find($returnType = 1)
    {
        $this->sql = ‘SELECT ‘ . $this->select . ‘ FROM ‘ . $this->table . $this->condition();
        return $this->row($this->sql, PDO::FETCH_ASSOC, $returnType);
    }
    /**
     * 根据查询条件返回多条记录
     */
    public function findAll($offset = 0, $limit = 0, $orderBy = ‘‘, $groupBy = ‘‘)
    {
        $this->sql = ‘SELECT ‘ . $this->select . ‘ FROM ‘ . $this->table . $this->condition();
        return $this->rows($this->sql, $offset, $limit, $orderBy, $groupBy);
    }
    /**
     * 删除数据
     */
    public function delete()
    {
        $this->sql = ‘DELETE FROM ‘ . $this->table . $this->condition();
        $ret = $this->exec($this->sql);
        return $ret !== false;
    }
    /**
     * 设置各种查询条件
     * @param mixed $input
     */
    public function where(array $input)
    {
        $this->where = array_merge($this->where, $input);
        return $this;
    }
    /**
     * WHERE array 转换 SQL字符串
     * @return string
     */
    public function condition()
    {
        $condStr = ‘‘;
        if (!count($this->where)) return $condStr;
        $condStr = ‘ WHERE ‘;
        foreach ($this->where as $filed => $value) {
            if (is_array($value)) {
                foreach ($value as $operator => $operatorValue) {
                    $operator = strtoupper($operator);
                    if (is_array($operatorValue)) { //IN NOT IN 数组条件
                        $operatorValue = array_map(function ($mapValue) {
                            return $this->quote($mapValue);
                        }, $operatorValue);
                        $operatorValue = implode(‘,‘, $operatorValue);
                        $condStr .= ‘`‘ . $filed . ‘` ‘ . $operator . ‘ (‘ . $operatorValue . ‘) AND ‘;
                    } else {
                        //LIKE <= >= < > <>等符号
                        $operatorValue = $this->quote($operatorValue);
                        $condStr .= ‘`‘ . $filed . ‘` ‘ . $operator . ‘ ‘ . $operatorValue . ‘ AND ‘;
                    }
                }
            } else {
                // = 号
                $value = $this->quote($value);
                $condStr .= "`$filed` = $value AND ";
            }
        }
        //消除 AND
        return substr($condStr, 0, -4);
    }
    public function select($fields)
    {
        if (is_array($fields) && $fields) {
            $this->select = ‘`‘ . implode(‘`,`‘, $fields) . ‘`‘;
        } else {
            $this->select = $fields;
        }
        return $this;
    }
    /**
     * 设置数据表名称，值
     * @param bool $name
     * @param mixed $fields
     */
    public function table($name, $fields = array())
    {
        $this->table = $name;
        $this->fields = $fields;
        return $this;
    }
    /**
     * 重置条件
     * @return $this
     */
    public function reset()
    {
        $this->sql = ‘‘;
        $this->select = ‘*‘;
        $this->where = array();
        return $this;
    }
    /**
     * @param array $data
     * 拼接key valure 数组为 = 连接的数据
     */
    public function joinKeyVal($data)
    {
        $arr = array();
        foreach ($data as $k => $v) {
            if ($this->fields && is_array($this->fields) && is_string($k)) {
                if (in_array($k, $this->fields)) {
                    if (is_null($v)) {
                        array_push($arr, sprintf("`%s`=NULL", $k));
                    } else {
                        array_push($arr, sprintf("`%s`=%s", $k, $this->quote($v)));
                    }
                } else {
                    continue;
                }
            } elseif (is_int($k)) {
                array_push($arr, $v);
            } else {
                array_push($arr, sprintf("`%s`=%s", $k, $this->quote($v)));
            }
        }
        return $arr;
    }
    /**
     * 给字符串,添加‘
     */
    public static function q($v)
    {
        return "‘" . str_replace(array("\\", "‘"), array(‘‘, "\\‘"), trim($v, "‘")) . "‘";
    }
    //当发生错误 STATE[HY000] CODE[2006] MSG[MySQL server has gone away]
    //时重建连接，检测到此错误时，调用方可以重试查询
    public function errorInfo()
    {
        $errInfo = parent::errorInfo();
        if ($errInfo[0] == ‘HY000‘ && $errInfo[1] == 2006) {
            $this->reConnect();
        }
        if ($this->stmt instanceof PDOStatement) { //绑定参数的方式执行sql出错
            $errInfo = $this->stmt->errorInfo();
            $errInfo[‘param‘] = $this->param;
        }
        $errInfo[‘sql‘] = $this->sql;
        return $errInfo;
    }
    public function exec($statement)
    {
        //$this->debug($statement);
        $this->msg = null;
        $ret = parent::exec($statement);
        if ($ret === false) {
            $this->msg = $this->errorInfo();
            //重试
            if ($this->msg[0] == ‘HY000‘ && $this->msg[1] == 2006) {
                $ret = parent::exec($statement);
                if ($ret !== false) {
                    $this->msg = null;
                }
            }
        }
        return $ret;
    }
    public function query($statement)
    {
        //$this->debug($statement);
        $this->msg = null;
        $ret = parent::query($statement);
        if ($ret === false) {
            $this->msg = $this->errorInfo();
            //重试
            if ($this->msg[0] == ‘HY000‘ && $this->msg[1] == 2006) {
                $ret = parent::query($statement);
                if ($ret !== false) {
                    $this->msg = null;
                }
            }
        }
        return $ret;
    }
    /**
     * 执行一条SQL语句并返回影响的行数，执行成功可能也返回0，执行失败则返回false
     * @param $sql
     * @param array $param
     * @return bool|int
     */
    public function execute($sql, $param = array())
    {
        $this->msg = null;
        $stmt = $this->prepareStatement($sql, $param);
        if ($stmt->execute()) {
            return intval($stmt->rowCount());
        } else {
            $this->msg = $this->errorInfo();
            //重试
            if ($this->msg[0] == ‘HY000‘ && $this->msg[1] == 2006) {
                $stmt = $this->prepareStatement($sql, $param);
                if ($stmt->execute()) {
                    $this->msg = null;
                    return intval($stmt->rowCount());
                } else {
                    return false;
                }
            } else {
                return false;
            }
        }
    }
    /**
     * 返回一个PDOStatement实例
     * @param $sql string，SQL语句，可以带占位符
     * @param array $param
     * @return bool|PDOStatement
     */
    private function prepareStatement($sql, $param = array())
    {
        try {
            $this->msg = null;
            $this->sql = $sql;
            $this->param = $param;
            $stmt = $this->prepare($sql);
            foreach ($param as $k => $v) {
                if (is_string($k) && substr($k, 0, 5) == ‘:INT_‘) {
                    $stmt->bindValue($k, $v, PDO::PARAM_INT);
                } elseif (is_int($k)) {
                    $stmt->bindValue($k + 1, $v, PDO::PARAM_STR);
                } else {
                    $stmt->bindValue($k, $v, PDO::PARAM_STR);
                }
            }
            $this->stmt = $stmt;
            return $stmt;
        } catch (\Exception $e) {
            $this->msg = $this->errorInfo();
            //重试
            if ($this->msg[0] == ‘HY000‘ && $this->msg[1] == 2006) {
                try {
                    $stmt = $this->prepare($sql);
                    foreach ($param as $k => $v) {
                        if (is_string($k) && substr($k, 0, 5) == ‘:INT_‘) {
                            $stmt->bindValue($k, $v, PDO::PARAM_INT);
                        } elseif (is_int($k)) {
                            $stmt->bindValue($k + 1, $v, PDO::PARAM_STR);
                        } else {
                            $stmt->bindValue($k, $v, PDO::PARAM_STR);
                        }
                    }
                    $this->stmt = $stmt;
                    $this->msg = null;
                    return $stmt;
                } catch (\Exception $e) {
                    return false;
                }
            } else {
                return false;
            }
        }
    }
}