CI框架AR数据库操作常用函数总结

$this->db->select();  //选择查询的字段$this->db->select_max();$this->db->select_min();$this->db->select_avg();$this->db->select_sum();$this->db->from();   //选择表名$this->db->join();$this->db->get();   //得到查询结果$this->db->get_where();$this->db->where();$this->db->or_where();$this->db->where_in();$this->db->or_where_in();$this->db->where_not_in();$this->db->or_where_not_in();$this->db->like();$this->db->or_like();$this->db->not_like();$this->db->or_not_like();$this->db->group_by();$this->db->distinct();$this->db->having();$this->db->or_having();$this->db->order_by();$this->db->limit();$this->db->count_all_results();

$this->db->insert();

$this->db->set();$this->db->update();

$this->db->delete();

$this->db->empty_table();$this->db->truncate();

$this->db->start_cache()$this->db->stop_cache()$this->db->flush_cache()

result()  //返回对象数组result_array() //返回二维数组row()   //返回一个对象row_array()  //返回一维数组num_rows()  //返回查询的行数num_fields() //返回查询结果的字段数free_result() //释放查询所占的资源内存

$this->db->insert_id()  //获取刚刚插入的id$this->db->affected_rows() //修改或插入影响的行数$this->db->count_all();  //统计记录的总条数 这一函数加入where条件无效$this->db->last_query();  //最后一条执行的sql语句//注意以下两个函数仅返回sql语句 不执行sql语句$data = array('name' => $name, 'email' => $email, 'url' => $url);$str = $this->db->insert_string('table_name', $data);$data = array('name' => $name, 'email' => $email, 'url' => $url);$where = "author_id = 1 AND status = 'active'";$str = $this->db->update_string('table_name', $data, $where); //返回正确格式的更新字符串