PHP封装类似thinkphp连贯操作数据库Db类与简单应用示例

<?php
header("Content-Type:text/html;charset=utf-8");
/**
*php操作mysql的工具类
*/
class Db{
private $_db = null;//数据库连接句柄
private $_table = null;//表名
private $_where = null;//where条件
private $_order = null;//order排序
private $_limit = null;//limit限定查询
private $_group = null;//group分组
private $_configs = array(
'hostname' =  'localhost',
'dbname'  =  'test',
'username' =  'root',
'password' =  '1234'
);//数据库配置
/**
* 构造函数，连接数据库
*/
public function __construct(){
$link = $this- _db;
if(!$link){
$db = mysqli_connect($this- _configs['hostname'],$this- _configs['username'],$this- _configs['password'],$this- _configs['dbname']);
mysqli_query($db,"set names utf8");
if(!$db){
$this- ShowException("错误信息".mysqli_connect_error());
}
$this- _db = $db;
}
}
/**
* 获取所有数据
*
* @param   <type   $table The table
*
* @return   boolean All.
*/
public function getAll($table=null){
$link = $this- _db;
if(!$link)return false;
$sql = "SELECT * FROM {$table}";
$data = mysqli_fetch_all($this- execute($sql));
return $data;
}
public function table($table){
$this- _table = $table;
return $this;
}
/**
* 实现查询操作
*
* @param   string  $fields The fields
*
* @return   boolean ( description_of_the_return_value )
*/
public function select($fields="*"){
$fieldsStr = '';
$link = $this- _db;
if(!$link)return false;
if(is_array($fields)){
$fieldsStr = implode(',', $fields);
}elseif(is_string($fields)&&!empty($fields)){
$fieldsStr = $fields;
}
$sql = "SELECT {$fields} FROM {$this- _table} {$this- _where} {$this- _order} {$this- _limit}";
$data = mysqli_fetch_all($this- execute($sql));
return $data;
}
/**
* order排序
*
* @param   string  $order The order
*
* @return   boolean ( description_of_the_return_value )
*/
public function order($order=''){
$orderStr = '';
$link = $this- _db;
if(!$link)return false;
if(is_string($order)&&!empty($order)){
$orderStr = "ORDER BY ".$order;
}
$this- _order = $orderStr;
return $this;
}
/**
* where条件
*
* @param   string $where The where
*
* @return   <type  ( description_of_the_return_value )
*/
public function where($where=''){
$whereStr = '';
$link = $this- _db;
if(!$link)return $link;
if(is_array($where)){
foreach ($where as $key =  $value) {
if($value == end($where)){
$whereStr .= "`".$key."` = '".$value."'";
}else{
$whereStr .= "`".$key."` = '".$value."' AND ";
}
}
$whereStr = "WHERE ".$whereStr;
}elseif(is_string($where)&&!empty($where)){
$whereStr = "WHERE ".$where;
}
$this- _where = $whereStr;
return $this;
}
/**
* group分组
*
* @param   string  $group The group
*
* @return   boolean ( description_of_the_return_value )
*/
public function group($group=''){
$groupStr = '';
$link = $this- _db;
if(!$link)return false;
if(is_array($group)){
$groupStr = "GROUP BY ".implode(',',$group);
}elseif(is_string($group)&&!empty($group)){
$groupStr = "GROUP BY ".$group;
}
$this- _group = $groupStr;
return $this;
}
/**
* limit限定查询
*
* @param   string $limit The limit
*
* @return   <type  ( description_of_the_return_value )
*/
public function limit($limit=''){
$limitStr = '';
$link = $this- _db;
if(!$link)return $link;
if(is_string($limit)||!empty($limit)){
$limitStr = "LIMIT ".$limit;
}elseif(is_numeric($limit)){
$limitStr = "LIMIT ".$limit;
}
$this- _limit = $limitStr;
return $this;
}
/**
* 执行sql语句
*
* @param   <type   $sql  The sql
*
* @return   boolean ( description_of_the_return_value )
*/
public function execute($sql=null){
$link = $this- _db;
if(!$link)return false;
$res = mysqli_query($this- _db,$sql);
if(!$res){
$errors = mysqli_error_list($this- _db);
$this- ShowException("报错啦！<br/ 错误号：".$errors[0]['errno']."<br/ SQL错误状态：".$errors[0]['sqlstate']."<br/ 错误信息：".$errors[0]['error']);
die();
}
return $res;
}
/**
* 插入数据
*
* @param   <type   $data  The data
*
* @return   boolean ( description_of_the_return_value )
*/
public function insert($data){
$link = $this- _db;
if(!$link)return false;
if(is_array($data)){
$keys = '';
$values = '';
foreach ($data as $key =  $value) {
$keys .= "`".$key."`,";
$values .= "'".$value."',";
}
$keys = rtrim($keys,',');
$values = rtrim($values,',');
}
$sql = "INSERT INTO `{$this- _table}`({$keys}) VALUES({$values})";
mysqli_query($this- _db,$sql);
$insertId = mysqli_insert_id($this- _db);
return $insertId;
}
/**
* 更新数据
*
* @param   <type  $data  The data
*
* @return   <type  ( description_of_the_return_value )
*/
public function update($data){
$link = $this- _db;
if(!$link)return $link;
if(is_array($data)){
$dataStr = '';
foreach ($data as $key =  $value) {
$dataStr .= "`".$key."`='".$value."',";
}
$dataStr = rtrim($dataStr,',');
}
$sql = "UPDATE `{$this- _table}` SET {$dataStr} {$this- _where} {$this- _order} {$this- _limit}";
$res = $this- execute($sql);
return $res;
}
/**
* 删除数据
*
* @return   <type  ( description_of_the_return_value )
*/
public function delete(){
$link = $this- _db;
if(!$link)return $link;
$sql = "DELETE FROM `{$this- _table}` {$this- _where}";
$res = $this- execute($sql);
return $res;
}
/**
* 异常信息输出
*
* @param   <type  $var  The variable
*/
private function ShowException($var){
if(is_bool($var)){
var_dump($var);
}else if(is_null($var)){
var_dump(NULL);
}else{
echo "<pre style='position:relative;z-index:1000;padding:10px;border-radius:5px;background:#F5F5F5;border:1px solid #aaa;font-size:14px;line-height:18px;opacity:0.9;' ".print_r($var,true)."</pre ";
}
}
}
$db = new Db();
//查询操作
var_dump($db- table('user')- where('id   2')- order('id desc')- limit('2,4')- select());
//插入操作
var_dump($db- table('user')- insert(array('username'= 'user','password'= 'pwd')));
//更新操作
var_dump($db- table('user')- where('id = 1')- update(array('username'= 'user1','password'= 'pwd1')));
//删除操作
var_dump($db- table('user')- where('id = 1')- delete());