<?php
/*
*describe:单例模式 数据库类
单例模式的必要条件
(1)私有的构造方法-为了防止在类外使用new关键字实例化对象
(2)私有的成员属性-为了防止在类外引入这个存放对象的属性
(3)私有的克隆方法-为了防止在类外通过clone成生另一个对象
(4)公有的静态方法-为了让用户进行实例化对象的操作
*/
header("content-type:text/html;charset=utf-8");
final class DB{
private $charset = "utf8"; //字符串编码
private $link = NULL; //数据库连接
private static $instance = NULL; //存储对象
//初始化
private function __construct($hostfield,$userfield,$password,$datebase){
$this->link = mysqli_connect($hostfield,$userfield,$password,$datebase);
if(!$this->link){
die("连接失败: " . mysqli_connect_error());
}
mysqli_query($this->link,"SET fieldS ".$this->charset);
return $this->link;
}
//防止克隆
private function __clone(){}
//静态公共接口
public static function getInstance($hostfield,$userfield,$password,$datebase){
if(!self::$instance instanceof self){
self::$instance = new DB($hostfield,$userfield,$password,$datebase);
}
return self::$instance;
}
/*
*describe:查询单个字段
*@param $field type:string 传入需要筛选的字段
*@param $table_name type:string 需要查询的表名
*@param $where type:array 需要筛选的where条件
*/
public function getField($field="",$table_name="",$where=""){
$where_string = "";
//where条件
$where_string = $this->getWhere($where);
if(is_string($field)){
//组装sql
$sql = "SELECT {$field} FROM {$table_name} WHERE {$where_string}";
$result = mysqli_query($this->link,$sql);
while($res = mysqli_fetch_array($result,MYSQL_ASSOC)){
$info[] = $res;
}
//若只有一个数组，则返回一维数组
if(count($info)==1){
return $info[0];
}else{
return $info;
}
}
}
/*
*describe:查询单条语句
*@param $sql 查询语句
*@param $type 返回数组的类型
* MYSQL_ASSOC - 关联数组(默认)
* MYSQL_NUM - 数字数组
* MYSQL_BOTH -同时产生关联和数字数组
*/
public function getRow($sql,$type=MYSQL_ASSOC){
$result = mysqli_query($this->link,$sql);
$res = mysqli_fetch_array($result,$type);
return $res;
}
/*
*describe:查询多条语句
*@param $sql 查询语句
*@param $type 返回数组的类型
* MYSQL_ASSOC - 关联数组(默认)
* MYSQL_NUM - 数字数组
* MYSQL_BOTH -同时产生关联和数字数组
*/
public function getRows($sql,$type=MYSQL_ASSOC){
$result = mysqli_query($this->link,$sql);
while($rows = mysqli_fetch_array($result,$type)){
$res[] = $rows;
}
return $res;
}
/*
*describe:增加语句
*@param type:array or string $info 传入的值
若为数组则进行拼接SQL语句，并新增 返回新增的ID
若传入的为SQL语句则直接执行，返回新增的ID
*@param $table_name 为需要新增的表名(可选)
*/
public function add($info,$table_name = ""){
//判断是否为数组，进行SQL拼接
if(is_array($info)){
$field = "";
$val ="";
$fields = "";
$vals ="";
foreach($info as $k=>$v){
$field .= "`".$k."`,";
$val .= "'".$v."',";
}
//$fields = substr($field,0,strlen($field)-1);
//$vals = substr($val,0,strlen($val)-1);
$fields = trim($field,",");
$vals = trim($val,",");
$sql = "INSERT INTO {$table_name} ({$fields}) VALUES ({$vals})";
if(mysqli_query($this->link,$sql)){
return mysqli_insert_id($this->link);
}else{
echo "error:".$sql."<br/>".mysqli_error($this->link);
}
//判断是否为SQL语句
}else if(is_string($info)){
if(mysqli_query($this->link,$info)){
return mysqli_insert_id($this->link);
}else{
echo "error:".$info."<br/>".mysqli_error($this->link);
}
}else{
echo "error";
}
}
/*
*describe:更新
*@param type:array $info 传入的修改的数组
*@param type:string $table_name 需修改的表名
*@param type:array $where 修改的where条件,传入数组
*/
public function update($info,$table_name = "",$where=""){
//判断是否是数组,进行SQL拼接
if(is_array($info)){
$field = "";
$fields = "";
//拼接修改语句
foreach($info as $k=>$v){
$field .= "`{$k}`='{$v}',";
}
$fields = trim($field,",");
//拼接where条件
$where_string = "";
$where_string = $this->getWhere($where);
//拼接SQL
$sql = "UPDATE {$table_name} SET {$fields} where {$where_string}";
echo $sql;
die();
if(mysqli_query($this->link,$sql)){
return mysqli_affected_rows($this->link);
}else{
echo "error:".$sql."<br/>".mysqli_error($this->link);
}
}else{
echo "error";
}
}
/*
*describe:删除
*@param $where type:array 传入需要删除的where条件 为数组
*@param $table_name type:string 需要删除的表名
*/
public function del($where,$table_name=""){
if(is_array($where)){
$where_string ="";
//拼接where条件
$where_string = $this->getWhere($where);
$sql = "DELETE FROM {$table_name} WHERE {$where_string}";
if(mysqli_query($this->link,$sql)){
return mysqli_affected_rows($this->link);
}else{
echo "error:".$sql."<br/>".mysqli_error($this->link);
}
}else{
echo "error";
}
}
/*
*describe:执行原生sql
*@param $sql type:string 需要执行的sql
*/
public function query($sql){
if(mysqli_query($this->link,$sql)){
return mysqli_affected_rows($this->link);
}else{
echo "error:".$sql."<br/>".mysqli_error($this->link);
}
}
/*
*describe:拼接where条件
*@param $where type:array 传入where为数组的条件
*/
private function getWhere($where){
$where_string = "";
if(is_array($where)){
foreach($where as $k=>$v){
if(is_array($v)){
foreach($v as $kk=>$vv){
$where_string .= "`{$k}` {$kk} '{$vv}' AND ";
}
}else{
$where_string .= "`{$k}`='{$v}' AND ";
}
}
}
return rtrim($where_string,"AND ");
}
}
//测试 mysql类
$class = DB::getInstance("localhost","root","123456","test");
$data = array(
"city_name"=>"test12222222",
"pid"=>"111111",
);
$where = array(
"id"=>"438",
"city_name"=>array("like"=>"%test%"),
);
//var_dump($class->query("DELETE FROM city WHERE `city_name` LIKE '%test%'"));
//var_dump($class->add($data,"city"));
//var_dump($class->del($where,"city"));
//var_dump($class->update($data,"city",$where));
//var_dump($class->getField("city_name,pid","city",$where));单例模式 封装PHP的mysql类
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转载自blog.csdn.net/superman_xing/article/details/80450492
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