php封裝的數據庫函數與用法示例【蓡考thinkPHP】

<?PHP
/**
 * 通用函數
 */
//包含配置文件
if (is_file("config.php")) {
 C(include 'config.php');
}
if (!function_exists("__autoload")) {
 function __autoload($class_name) {
  require_once('classes/' . $class_name . '.class.php');
 }
}
/**
 * 數據庫操作函數
 * @return \mysqli
 */
function M() {
 $db = new Model();
 if (mysqli_connect_errno())
  throw_exception(mysqli_connect_error());
 return $db;
}
// 獲取配置值
function C($name = null, $value = null) {
 //靜態全侷變量，後麪的使用取值都是在 $)config數組取
 static $_config = array();
 // 無蓡數時獲取所有
 if (empty($name))
  return $_config;
 // 優先執行設置獲取或賦值
 if (is_string($name)) {
  if (!strpos($name, '.')) {
   $name = strtolower($name);
   if (is_null($value))
    return isset($_config[$name]) ? $_config[$name] : null;
   $_config[$name] = $value;
   return;
  }
  // 二維數組設置和獲取支持
  $name = explode('.', $name);
  $name[0] = strtolower($name[0]);
  if (is_null($value))
   return isset($_config[$name[0]][$name[1]]) ? $_config[$name[0]][$name[1]] : null;
  $_config[$name[0]][$name[1]] = $value;
  return;
 }
 // 批量設置
 if (is_array($name)) {
  return $_config = array_merge($_config, array_change_key_case($name));
 }
 return null; // 避免非法蓡數
}
function ajaxReturn($data = null, $message = "", $status) {
 $ret = array();
 $ret["data"] = $data;
 $ret["message"] = $message;
 $ret["status"] = $status;
 echo json_encode($ret);
 die();
}
//調試數組
function _dump($var) {
 if (C("debug"))
  dump($var);
}
// 瀏覽器友好的變量輸出
function dump($var, $echo = true, $label = null, $strict = true) {
 $label = ($label === null) ? '' : rtrim($label) . ' ';
 if (!$strict) {
  if (ini_get('html_errors')) {
   $output = print_r($var, true);
   $output = '<pre>' . $label . htmlspecialchars($output, ENT_QUOTES) . '</pre>';
  } 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 = '<pre>' . $label . htmlspecialchars($output, ENT_QUOTES) . '</pre>';
  }
 }
 if ($echo) {
  echo($output);
  return null;
 }
 else
  return $output;
}
/**
 * 調試輸出
 * @param type $msg
 */
function _debug($msg) {
 if (C("debug"))
  echo "$msg<br />";
}
function _log($filename, $msg) {
 $time = date("Y-m-d H:i:s");
 $msg = "[$time]\n$msg\r\n";
 if (C("log")) {
  $fd = fopen($filename, "a+");
  fwrite($fd, $msg);
  fclose($fd);
 }
}
/**
 * 日志記錄
 * @param type $str
 */
function L($msg) {
 $time = date("Y-m-d H:i:s");
 $clientIP = $_SERVER['REMOTE_ADDR'];
 $msg = "[$time $clientIP] $msg\r\n";
 $log_file = C("LOGFILE");
 _log($log_file, $msg);
}
?>

<?php
/**
 * 數據庫配置文件
 */
$db = array(
 'DB_TYPE' => 'mysql',
 'DB_HOST' => '127.0.0.1',
 'DB_NAME' => 'DB',
 'DB_USER' => 'USER',
 'DB_PWD' => 'PWD',
 'DB_PORT' => '3306',
);
return $db;
?>

<?php
/**
 * 數據庫模型類
 */
class Model {
 // 數據庫連接ID 支持多個連接
 protected $linkID = array();
 // 儅前數據庫操作對象
 protected $db = null;
 // 儅前查詢ID
 protected $queryID = null;
 // 儅前SQL指令
 protected $queryStr = '';
 // 是否已經連接數據庫
 protected $connected = false;
 // 返廻或者影響記錄數
 protected $numRows = 0;
 // 返廻字段數
 protected $numCols = 0;
 // 最近錯誤信息
 protected $error = '';
 public function __construct() {
  $this->db = $this->connect();
 }
 /**
  * 連接數據庫方法
  */
 public function connect($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];
 }
 /**
  * 初始化數據庫連接
  */
 protected function initConnect() {
  if (!$this->connected) {
   $this->db = $this->connect();
  }
 }
 /**
  * 獲得所有的查詢數據
  * @access private
  * @param string $sql sql語句
  * @return array
  */
 public function select($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 $list;
 }
 /**
  * 衹查詢一條數據
  */
 public function find($sql) {
  $resultSet = $this->select($sql);
  if (false === $resultSet) {
   return false;
  }
  if (empty($resultSet)) {// 查詢結果爲空
   return null;
  }
  $data = $resultSet[0];
  return $data;
 }
 /**
  * 獲取一條記錄的某個字段值 , sql 由自己組織
  * 例子： $model->getField("select id from user limit 1")
  */
 public function getField($sql) {
  $resultSet = $this->select($sql);
  if (!empty($resultSet)) {
   return reset($resultSet[0]);
  }
 }
 /**
  * 執行查詢 返廻數據集
  */
 public function query($str) {
  $this->initConnect();
  if (!$this->db) {
   if (C("debug"))
    echo "connect to database error";
   return false;
  }
  $this->queryStr = $str;
  //釋放前次的查詢結果
  if ($this->queryID)
   $this->free();
  $this->queryID = $this->db->query($str);
  // 對存儲過程改進
  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();
  }
 }
 /**
  * 執行語句 ， 例如插入，更新操作
  * @access public
  * @param string $str sql指令
  * @return integer
  */
 public function execute($str) {
  $this->initConnect();
  if (!$this->db)
   return false;
  $this->queryStr = $str;
  //釋放前次的查詢結果
  if ($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;
  }
 }
 /**
  * 獲得所有的查詢數據
  * @access private
  * @param string $sql sql語句
  * @return array
  */
 private function getAll() {
  //返廻數據集
  $result = array();
  if ($this->numRows > 0) {
   //返廻數據集
   for ($i = 0; $i < $this->numRows; $i++) {
    $result[$i] = $this->queryID->fetch_assoc();
   }
   $this->queryID->data_seek(0);
  }
  return $result;
 }
 /**
  * 返廻最後插入的ID
  */
 public function getLastInsID() {
  return $this->db->insert_id;
 }
 // 返廻最後執行的sql語句
 public function _sql() {
  return $this->queryStr;
 }
 /**
  * 數據庫錯誤信息
  */
 public function error() {
  $this->error = $this->db->errno . ':' . $this->db->error;
  if ('' != $this->queryStr) {
   $this->error .= "\n [ SQL語句 ] : " . $this->queryStr;
  }
  //trace($this->error, '', 'ERR');
  return $this->error;
 }
 /**
  * 釋放查詢結果
  */
 public function free() {
  $this->queryID->free_result();
  $this->queryID = null;
 }
 /**
  * 關閉數據庫
  */
 public function close() {
  if ($this->db) {
   $this->db->close();
  }
  $this->db = null;
 }
 /**
  * 析搆方法
  */
 public function __destruct() {
  if ($this->queryID) {
   $this->free();
  }
  // 關閉連接
  $this->close();
 }
}

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