下面是官方手册上的例子
// Turn caching on
$this->db->cache_on();
$query = $this->db->query("SELECT * FROM mytable");
// Turn caching off for this one query
$this->db->cache_off();
$query = $this->db->query("SELECT * FROM members WHERE member_id = '$current_user'");
// Turn caching back on
$this->db->cache_on();
$query = $this->db->query("SELECT * FROM another_table");
在实际应用中,两条查询语句中间不免会有一些逻辑代码,这个时候的手动开关缓存命令应该紧挨着查询语句
$this->db->cache_on();
select ...
逻辑代码
$this->db->cache_off();
select ...