php封装的数据库函数与用法示例

本文实例讲述了php封装的数据库函数与用法。分享给大家供大家参考，具体如下：

从Thinkphp里面抽离出来的数据库模块，感觉挺好用

common.php：

' . $label . htmlspecialchars($output, ENT_QUOTES) . '

'; } else { $output = $label . print_r($var, true); } } else { ob_start(); var_dump($var); $output = ob_get_clean(); if (!extension_loaded('xdebug')) { $output = preg_replace("/]=>n(s+)/m", '] => ', $output); $output = '

' . $label . htmlspecialchars($output, ENT_QUOTES) . '

'; } } if ($echo) { echo($output); return null; } else return $output; } function _debug($msg) { if (C("debug")) echo "$msg
"; } function _log($filename, $msg) { $time = date("Y-m-d H:i:s"); $msg = "[$time]n$msgrn"; if (C("log")) { $fd = fopen($filename, "a+"); fwrite($fd, $msg); fclose($fd); } } function L($msg) { $time = date("Y-m-d H:i:s"); $clientIP = $_SERVER['REMOTE_ADDR']; $msg = "[$time $clientIP] $msgrn"; $log_file = C("LOGFILE"); _log($log_file, $msg); } ?>

config.php：

 'mysql',
 'DB_HOST' => '127.0.0.1',
 'DB_NAME' => 'DB',
 'DB_USER' => 'USER',
 'DB_PWD' => 'PWD',
 'DB_PORT' => '3306',
);
return $db;
?>

数据库模型类Model.class.php，放到classes/目录下：

db = $this->connect();
 }
 
 public function connect($config = '', $linkNum = 0) {
  if (!isset($this->linkID[$linkNum])) {
   if (empty($config))
    $config = array(
     'username' => C('DB_USER'),
     'password' => C('DB_PWD'),
     'hostname' => C('DB_HOST'),
     'hostport' => C('DB_PORT'),
     'database' => C('DB_NAME')
    );
   $this->linkID[$linkNum] = new mysqli($config['hostname'], $config['username'], $config['password'], $config['database'], $config['hostport'] ? intval($config['hostport']) : 3306);
   if (mysqli_connect_errno())
    throw_exception(mysqli_connect_error());
   $this->connected = true;
  }
  return $this->linkID[$linkNum];
 }
 
 protected function initConnect() {
  if (!$this->connected) {
   $this->db = $this->connect();
  }
 }
 
 public function select($sql) {
  $this->initConnect();
  if (!$this->db)
   return false;
  $query = $this->db->query($sql);
  $list = array();
  if (!$query)
   return $list;
  while ($rows = $query->fetch_assoc()) {
   $list[] = $rows;
  }
  return $list;
 }
 
 public function find($sql) {
  $resultSet = $this->select($sql);
  if (false === $resultSet) {
   return false;
  }
  if (empty($resultSet)) {// 查询结果为空
   return null;
  }
  $data = $resultSet[0];
  return $data;
 }
 
 public function getField($sql) {
  $resultSet = $this->select($sql);
  if (!empty($resultSet)) {
   return reset($resultSet[0]);
  }
 }
 
 public function query($str) {
  $this->initConnect();
  if (!$this->db) {
   if (C("debug"))
    echo "connect to database error";
   return false;
  }
  $this->queryStr = $str;
  //释放前次的查询结果
  if ($this->queryID)
   $this->free();
  $this->queryID = $this->db->query($str);
  // 对存储过程改进
  if ($this->db->more_results()) {
   while (($res = $this->db->next_result()) != NULL) {
    $res->free_result();
   }
  }
  //$this->debug();
  if (false === $this->queryID) {
   echo $this->error();
   return false;
  } else {
   $this->numRows = $this->queryID->num_rows;
   $this->numCols = $this->queryID->field_count;
   return $this->getAll();
  }
 }
 
 public function execute($str) {
  $this->initConnect();
  if (!$this->db)
   return false;
  $this->queryStr = $str;
  //释放前次的查询结果
  if ($this->queryID)
   $this->free();
  $result = $this->db->query($str);
  if (false === $result) {
   $this->error();
   return false;
  } else {
   $this->numRows = $this->db->affected_rows;
   $this->lastInsID = $this->db->insert_id;
   return $this->numRows;
  }
 }
 
 private function getAll() {
  //返回数据集
  $result = array();
  if ($this->numRows > 0) {
   //返回数据集
   for ($i = 0; $i < $this->numRows; $i++) {
    $result[$i] = $this->queryID->fetch_assoc();
   }
   $this->queryID->data_seek(0);
  }
  return $result;
 }
 
 public function getLastInsID() {
  return $this->db->insert_id;
 }
 // 返回最后执行的sql语句
 public function _sql() {
  return $this->queryStr;
 }
 
 public function error() {
  $this->error = $this->db->errno . ':' . $this->db->error;
  if ('' != $this->queryStr) {
   $this->error .= "n [ SQL语句 ] : " . $this->queryStr;
  }
  //trace($this->error, '', 'ERR');
  return $this->error;
 }
 
 public function free() {
  $this->queryID->free_result();
  $this->queryID = null;
 }
 
 public function close() {
  if ($this->db) {
   $this->db->close();
  }
  $this->db = null;
 }
 
 public function __destruct() {
  if ($this->queryID) {
   $this->free();
  }
  // 关闭连接
  $this->close();
 }
}

例子：

#include "common.php"
function test(){
 $model = M();
 $sql = "select * from test";
 $list = $model->query($sql);
 _dump($list);
}

更多关于PHP相关内容感兴趣的读者可查看本站专题：《php+mysql数据库操作入门教程》、《PHP基本语法入门教程》、《PHP运算与运算符用法总结》、《php面向对象程序设计入门教程》、《PHP网络编程技巧总结》、《PHP数组(Array)操作技巧大全》、《php字符串(string)用法总结》及《php常见数据库操作技巧汇总》

希望本文所述对大家PHP程序设计有所帮助。