PHP encapsulated database functions and usage

This article mainly introduces the database functions and usage of PHP encapsulation. It is based on the simplified database operation related code in thinkPHP, including functions such as database settings, connections, queries and log operations. It is simple and practical, and friends in need You can refer to the following

The examples in this article describe the database functions and usage of PHP encapsulation. Share it with everyone for your reference, the details are as follows:

The database module extracted from Thinkphp, I feel it is very easy to use

common.php：

<?PHP
/**
 * 通用函数
 */
//包含配置文件
if (is_file("config.php")) {
 C(include &#39;config.php&#39;);
}
if (!function_exists("__autoload")) {
 function __autoload($class_name) {
  require_once(&#39;classes/&#39; . $class_name . &#39;.class.php&#39;);
 }
}
/**
 * 数据库操作函数
 * @return \mysqli
 */
function M() {
 $db = new Model();
 if (mysqli_connect_errno())
  throw_exception(mysqli_connect_error());
 return $db;
}
// 获取配置值
function C($name = null, $value = null) {
 //静态全局变量，后面的使用取值都是在 $)config数组取
 static $_config = array();
 // 无参数时获取所有
 if (empty($name))
  return $_config;
 // 优先执行设置获取或赋值
 if (is_string($name)) {
  if (!strpos($name, &#39;.&#39;)) {
   $name = strtolower($name);
   if (is_null($value))
    return isset($_config[$name]) ? $_config[$name] : null;
   $_config[$name] = $value;
   return;
  }
  // 二维数组设置和获取支持
  $name = explode(&#39;.&#39;, $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]] = $value;
  return;
 }
 // 批量设置
 if (is_array($name)) {
  return $_config = array_merge($_config, array_change_key_case($name));
 }
 return null; // 避免非法参数
}
function ajaxReturn($data = null, $message = "", $status) {
 $ret = array();
 $ret["data"] = $data;
 $ret["message"] = $message;
 $ret["status"] = $status;
 echo json_encode($ret);
 die();
}
//调试数组
function _dump($var) {
 if (C("debug"))
  dump($var);
}
// 浏览器友好的变量输出
function dump($var, $echo = true, $label = null, $strict = true) {
 $label = ($label === null) ? &#39;&#39; : rtrim($label) . &#39; &#39;;
 if (!$strict) {
  if (ini_get(&#39;html_errors&#39;)) {
   $output = print_r($var, true);
   $output = &#39;<pre class="brush:php;toolbar:false">&#39; . $label . htmlspecialchars($output, ENT_QUOTES) . &#39;

'; } 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; } /** * 调试输出 * @param type $msg */ function _debug($msg) { if (C("debug")) echo "$msg
"; } function _log($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); } } /** * 日志记录 * @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); } ?>

config.php：

<?php
/**
 * 数据库配置文件
 */
$db = array(
 &#39;DB_TYPE&#39; => &#39;mysql&#39;,
 &#39;DB_HOST&#39; => &#39;127.0.0.1&#39;,
 &#39;DB_NAME&#39; => &#39;DB&#39;,
 &#39;DB_USER&#39; => &#39;USER&#39;,
 &#39;DB_PWD&#39; => &#39;PWD&#39;,
 &#39;DB_PORT&#39; => &#39;3306&#39;,
);
return $db;
?>

Database model class Model.class.php, put it in the classes/ directory:

<?php
/**
 * 数据库模型类
 */
class Model {
 // 数据库连接ID 支持多个连接
 protected $linkID = array();
 // 当前数据库操作对象
 protected $db = null;
 // 当前查询ID
 protected $queryID = null;
 // 当前SQL指令
 protected $queryStr = &#39;&#39;;
 // 是否已经连接数据库
 protected $connected = false;
 // 返回或者影响记录数
 protected $numRows = 0;
 // 返回字段数
 protected $numCols = 0;
 // 最近错误信息
 protected $error = &#39;&#39;;
 public function __construct() {
  $this->db = $this->connect();
 }
 /**
  * 连接数据库方法
  */
 public function connect($config = &#39;&#39;, $linkNum = 0) {
  if (!isset($this->linkID[$linkNum])) {
   if (empty($config))
    $config = array(
     &#39;username&#39; => C(&#39;DB_USER&#39;),
     &#39;password&#39; => C(&#39;DB_PWD&#39;),
     &#39;hostname&#39; => C(&#39;DB_HOST&#39;),
     &#39;hostport&#39; => C(&#39;DB_PORT&#39;),
     &#39;database&#39; => C(&#39;DB_NAME&#39;)
    );
   $this->linkID[$linkNum] = new mysqli($config[&#39;hostname&#39;], $config[&#39;username&#39;], $config[&#39;password&#39;], $config[&#39;database&#39;], $config[&#39;hostport&#39;] ? intval($config[&#39;hostport&#39;]) : 3306);
   if (mysqli_connect_errno())
    throw_exception(mysqli_connect_error());
   $this->connected = true;
  }
  return $this->linkID[$linkNum];
 }
 /**
  * 初始化数据库连接
  */
 protected function initConnect() {
  if (!$this->connected) {
   $this->db = $this->connect();
  }
 }
 /**
  * 获得所有的查询数据
  * @access private
  * @param string $sql sql语句
  * @return array
  */
 public function select($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 $list;
 }
 /**
  * 只查询一条数据
  */
 public function find($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;
 }
 /**
  * 获取一条记录的某个字段值 , sql 由自己组织
  * 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]);
  }
 }
 /**
  * 执行查询 返回数据集
  */
 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();
  }
 }
 /**
  * 执行语句 ， 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 = $str;
  //释放前次的查询结果
  if ($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;
  }
 }
 /**
  * 获得所有的查询数据
  * @access private
  * @param string $sql sql语句
  * @return array
  */
 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;
 }
 /**
  * 返回最后插入的ID
  */
 public function getLastInsID() {
  return $this->db->insert_id;
 }
 // 返回最后执行的sql语句
 public function _sql() {
  return $this->queryStr;
 }
 /**
  * 数据库错误信息
  */
 public function error() {
  $this->error = $this->db->errno . &#39;:&#39; . $this->db->error;
  if (&#39;&#39; != $this->queryStr) {
   $this->error .= "\n [ SQL语句 ] : " . $this->queryStr;
  }
  //trace($this->error, &#39;&#39;, &#39;ERR&#39;);
  return $this->error;
 }
 /**
  * 释放查询结果
  */
 public function free() {
  $this->queryID->free_result();
  $this->queryID = null;
 }
 /**
  * 关闭数据库
  */
 public function close() {
  if ($this->db) {
   $this->db->close();
  }
  $this->db = null;
 }
 /**
  * 析构方法
  */
 public function __destruct() {
  if ($this->queryID) {
   $this->free();
  }
  // 关闭连接
  $this->close();
 }
}

Example:

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

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