<?php

class DB

{

private $dbs = "";

private $fields = "*";

private $tables = null;

private $joins = null;

private $ons = null;

private $wheres = null;

private $limits = null;

private $orderby = null;

private $likes = null;

private $groupby = null;

private $sums = null;

private $field = null;

private $avgs = null;

private $counts = null;

private $maxs = null;

private $mins = null;

// 链接数据库

function __construct()

{

try {

$this->dbs = new PDO('mysql:host=主机地址;dbname=表名','用户名','密码');

} catch (PDOException $e) {

print "Error!: " . $e->getMessage() . "<br/>";

die();

}

}

// 各种查询

// 指定字段查询

public function field($data){

$this->fields = implode(",",$data);

return $this;

}

// 要查询的表名

public function table($table){

$this->tables = $table;

return $this;

}

// 内链接

public function join($table){

$this->joins = " inner join ".$table;

return $this;

}

// 左连接

public function leftjoin($table){

$this->joins = " left join ".$table;

return $this;

}

// 右链接

public function rightjoin($table){

$this->joins = " right join ".$table;

return $this;

}

// 关联关系

public function on($id,$gid){

$this->ons = " on ".$id.'='.$gid;

return $this;

}

// 条件

public function where($k,$v){

$this->wheres = " where ".$k.'='.$v;

return $this;

}

// 限制条件

public function limit($origin,$end){

$this->limits = " limit ".$origin.",".$end;

return $this;

}

public function order($id,$asc){

$this->orderby = " order by ".$id." ".$asc;

return $this;

}

// 模糊查询

public function like($k,$v){

$this->likes = " where"." ".$k." "." "." like "."'".'%'.$v.'%'."'";

return $this;

}

// 分组查询

public function group($name){

$this->groupby = " group by ".$name;

return $this;

}

// 求和

public function sum($v){

$this->sums = " sum"."(".$v.")"." ";

return $this;

}

// 平均值

public function avg($v){

$this->sums = " avg"."(".$v.")"." ";

return $this;

}

// 长度

public function count($v){

$this->counts = " count"."(".$v.")"." ";

return $this;

}

// 最大值

public function max($v){

$this->maxs = " max"."(".$v.")"." ";

return $this;

}

// 最小值

public function min($v){

$this->mins = " min"."(".$v.")"." ";

return $this;

}

// 查询语句

public function get(){

if ($this->sums == "" && $this->avgs == "" && $this->counts == "" && $this->maxs == "" && $this->mins == "") {

$sql = "select ".$this->fields." from ".$this->tables.$this->joins.$this->ons.$this->wheres.$this->limits.$this->orderby.$this->likes.$this->groupby;

}else{

$sql = "select ".$this->sums.$this->counts.$this->maxs.$this->mins.$this->avgs." from ".$this->tables.$this->joins.$this->ons.$this->wheres.$this->limits.$this->orderby.$this->likes.$this->groupby;

}

return $this->dbs->query($sql)->fetchAll(PDO::FETCH_ASSOC);

}

// 删除

public function del($id){

$sql = "delete from ".$this->tables." where id =".$id;

$res = $this->dbs->exec($sql);

return $res;

}

// 改

public function update($data,$id){

foreach ($data as $key => $value) {

@$str .= " ".$key." = "."'".$value."'"." , ";

}

$strs = substr($str,"0","-2");

$sql = "update ".$this->tables." set ".$strs." where id = ".$id;

return $this->dbs->exec($sql);

}

// 增

public function add($data){

$v = array_values($data);

$k = array_keys($data);

$k = implode(",",$k);

$v = implode("','",$v);

$v = "'".$v."'";

@$sql = "insert into"." ".$this->tables."(".$k.")".values."(".$v.")";

return $this->dbs->exec("$sql");

}

}

?>