PDO方法连接数据库是一种比较流行的方法：它的操作比较简单
如果只是简单的使用的话：

// 数据库连接          try {              $this->pdo = new \PDO("mysql:host=" . $hostname . ";port=" . $port . ";dbname=" . $database, $username, $password, array(\PDO::ATTR_PERSISTENT => true));          } catch(\PDOException $e) {              trigger_error('Error: Could not make a database link ( ' . $e->getMessage() . '). Error Code : ' . $e->getCode() . ' <br />');          }  // 调用方法很简单  $query=$pdo->query('SELECT id,name FROM user');  $row=$query->fetch();

但我们更多的使用是用于实际的项目中，有必要把pdo的操作方式封装成一个类

class mPDO   {        public $SqlBug = ''; // 记录mysql调试语句，可以查看完整的执行的mysql语句      private $pdo = null; // pdo连接      private $statement = null;             public function __construct($hostname, $username, $password, $database, $charset, $port = "3306")       {          try {              $this->pdo = new \PDO("mysql:host=" . $hostname . ";port=" . $port . ";dbname=" . $database, $username, $password, array(\PDO::ATTR_PERSISTENT => true));          } catch(\PDOException $e) {              trigger_error('Error: Could not make a database link ( ' . $e->getMessage() . '). Error Code : ' . $e->getCode() . ' <br />');          }            $this->pdo->exec("SET NAMES '" . $charset . "'");          $this->pdo->exec("SET CHARACTER SET " . $charset);          $this->pdo->exec("SET CHARACTER_SET_CONNECTION=" . $charset);          $this->pdo->exec("SET SQL_MODE = ''");        }        public function prepare($sql)       {          $this->statement = $this->pdo->prepare($sql);           $this -> SqlBug .= "\n". '<!--DebugSql: ' . $sql . '-->' . "\n";      }        public function bindParam($parameter, $variable, $data_type = PDO::PARAM_STR, $length = 0)       {          if ($length) {              $this->statement->bindParam($parameter, $variable, $data_type, $length);          } else {              $this->statement->bindParam($parameter, $variable, $data_type);          }      }        public function execute()       {          try {              if ($this->statement && $this->statement->execute()) {                  $data = array();                    while ($row = $this->statement->fetch(PDO::FETCH_ASSOC)) {                      $data[] = $row;                  }                    $result = new stdClass();                  $result->row = (isset($data[0])) ? $data[0] : array();                  $result->rows = $data;                  $result->num_rows = $this->statement->rowCount();              }          } catch(PDOException $e) {              trigger_error('Error: ' . $e->getMessage() . ' Error Code : ' . $e->getCode());          }      }        public function query($sql, $params = array())       {          $this->statement = $this->pdo->prepare($sql);          $result = false;            $this -> SqlBug .= "\n". '<!--DebugSql: ' . $sql . '-->' . "\n";            try {              if ($this->statement && $this->statement->execute($params)) {                  $data = array();                    while ($row = $this->statement->fetch(\PDO::FETCH_ASSOC)) {                      $data[] = $row;                  }                    $result = new \stdClass();                  $result->row = (isset($data[0]) ? $data[0] : array());                  $result->rows = $data;                  $result->num_rows = $this->statement->rowCount();              }          } catch (PDOException $e) {              trigger_error('Error: ' . $e->getMessage() . ' Error Code : ' . $e->getCode() . ' <br />' . $sql);              exit();          }            if ($result) {              return $result;          } else {              $result = new stdClass();              $result->row = array();              $result->rows = array();              $result->num_rows = 0;              return $result;          }      }        public function executeUpdate($sql)      {          return $this->pdo->exec($sql);      }        /**       * 获得所有查询条件的值        */      public function fetchAll($sql, $params = array())       {          $rows = $this->query($sql, $params)->rows;          return !empty($rows) ? $rows : false;      }        /**       * 获得单行记录的值       */      public function fetchAssoc($sql, $params = array())       {          $row = $this->query($sql, $params)->row;          return !empty($row) ? $row : false;      }        /**       * 获得单个字段的值       */      public function fetchColumn($sql, $params = array())       {          $data = $this->query($sql, $params)->row;           if(is_array($data)) {              foreach ($data as $value) {                  return $value;              }          }            return false;      }        /**       * 返回statement记录集的行数       */      public function rowCount($sql, $params = array())      {          return $this->query($sql, $params)->num_rows;      }        /**       * 插入数据       * @param   string  $table      表名       * @param   Array   $data       数据       * @return  int     InsertId    新增ID       */      public function _insert($table, $data)      {          if (!is_array($data) || count($data) == 0) {              return 0;          }            $field_arr = array();          foreach ($data as $key=>$val) {              $field_arr[] = " `$key` = '$val' ";          }            $sql = "INSERT INTO " . $table . " SET " . implode(',', $field_arr);          $this -> query($sql);            return $this->getLastId();      }        /**       * 更新数据       * @param   string  $table      表名       * @param   Array   $data       数据       * @param   string  $where      更新条件       * @return  int  影响数       */      public function _update($table, $data, $where = '')      {          // $this -> Affected = 0;          if(empty($where)) {              return 0;          }          if (!is_array($data) || count($data) == 0) {              return 0;          }            $field_arr = array();          foreach ($data as $key=>$val)              $field_arr[] = " `$key` = '$val' ";            $sql = "UPDATE " . $table . " SET " . implode(',', $field_arr) . " WHERE " . $where;            return $this->pdo->exec($sql);      }        /**       * 获得影响集合中       */      public function _delete($table, $where = "")      {          if(empty($where)) {              return 0;          }          $sql = "DELETE FROM " . $table . " WHERE " . $where;            return $this->pdo->exec($sql);      }        /**       * 获得影响集合中       */      public function countAffected()       {          if ($this->statement) {              return $this->statement->rowCount();          } else {              return 0;          }      }        /*       * 获得插入id       */      public function getLastId()       {          return $this->pdo->lastInsertId();      }        public function escape($value) {          $search = array("\\", "\0", "\n", "\r", "\x1a", "'", '"');          $replace = array("\\\\", "\\0", "\\n", "\\r", "\Z", "\'", '\"');          return str_replace($search, $replace, $value);      }        /**       * 返回错误信息也包括错误号       */      public function errorInfo()       {          return $this->statement->errorInfo();      }        /**       * 返回错误号       */      public function errorCode()       {          return $this->statement->errorCode();      }        public function __destruct()      {          $this->pdo = null;      }  }

// 当然还有mysql_connect,mysqli的方法都可以连接数据库了

转载: php pdo方式连接mysql数据库