1.准备news表格，id,title,slug,text

2.新建Crud.php，并继承

class Crud extends CI_Controller 3.     public function __construct()     {         parent::__construct();         $this->load->database();     } 4.新增记录     public function c()     {        $arrNews=array();        $arrNews['title']='第一条标题';        $arrNews['slug']='A';        $arrNews['text']='this is a test';        var_dump($this ->db->insert('news',$arrNews)) ;        echo $this ->db->insert_id();     } 5.通过id读取一条 public function r()     {        $arrParams=$this->uri->uri_to_assoc();        if(empty($arrParams)||empty($arrParams['id'])){            echo 'no';            return;        }        $this->db->from("news")->where('id=',$arrParams['id']);        $res=$this->db->get();        var_dump($res->result());
    }   6.读取全部     public function ra()     {        $res=$this->db->get("news");        var_dump($res->result());     }     public function u()     {         $this->db->set('title','test for title 2');         $this->db->where('id',2);         var_dump($this->db->update('news'));     } 7.删除一条
    public function d()     {         $this->db->where('id',3);        var_dump($this->db->delete('news'));     }