本文实例讲述了php通过前序遍历树实现无需递归的无限极分类.分享给大家供大家参考.具体如下: 大家通常都是使用递归实现无限极分类都知道递归效率很低,下面介绍一种改进的前序遍历树算法,不适用递归实现无限极分类,在大数据量实现树状层级结构的时候效率更高. sql代码如下: CREATE TABLE IF NOT EXISTS `category` ( `id` int(11) NOT NULL AUTO_INCREMENT, `title` varchar(50) NOT NULL, `lft` i
--with用法 --可以这么理解 with SQL语句变量或者叫临时表名 as( SQL语句 ) select * from SQL语句变量或者叫临时表名 --递归调用 with CTE as( select ZTBM_ID,ztbm_name,ParentId from TB_ZYM_ZTBM where ParentId is null or ParentId='' union all select a.ZTBM_ID,a.ztbm_name,a.ParentId from TB_ZYM_
两个实体,其实一个实体也能构造出来,我这里是为了增加一个 checkbox //第一个实体 public class person { public int no { get; set; } public string name { get; set; } public ObservableCollection<person> child { get; set; } } //第二个实体 public class inst
Before being an ubiquous communications gadget, a mobilewas just a structure made of strings and wires suspendingcolourfull things. This kind of mobile is usually found hangingover cradles of small babies.The gure illustrates a simple mobile. It is j