php无限循环 [英] php infinite loop

问题描述

这个函数给了我一个无限循环

This function gives me an infinite loop

function getCats($parent,$level){
    // retrieve all children of $parent
    $result = "";
    $query = "SELECT title,parent_id from t_cats where parent_id = '$parent'";

    if($rs = C_DB::fetchRecordset($query)){
        while($row = C_DB::fetchRow($rs)){
            $result .= str_repeat($parent,$level).$row['title']."\n";
            getCats($row['parent_id'],$level+1);
        }
    }

    return $result;
} 

这是我的数据库表

CREATE TABLE  `db`.`t_cats` (
  `ID` int(10) unsigned NOT NULL auto_increment,
  `datasource_id` int(10) unsigned default '0',
  `version` char(10) character set latin1 default 'edit',
  `status` char(10) character set latin1 default 'new',
  `modified_date` datetime default NULL,
  `modified_by` int(10) unsigned default '0',
  `title` char(255) character set latin1 default NULL,
  `parent_id` int(11) default NULL,
  PRIMARY KEY  (`ID`),
  KEY `idx_datasource_id` (`datasource_id`)
) ENGINE=MyISAM AUTO_INCREMENT=50 DEFAULT CHARSET=utf8;

我只是想让我的类别列表递归.

I just want to be able to get my list of categories recursive.

但我做错了什么?

function getCats($parent,$level){
                // retrieve all children of $parent
                $result ="";
                $query = "SELECT title,parent_id from t_cats where parent_id = '$parent'";
                if($rs = C_DB::fetchRecordset($query)){
                    while($row = C_DB::fetchRow($rs)){
                        $result.= str_repeat($parent,$level).$row['title']."\n";
                        getCats($row['id'],$level + 1   );
                    }
                }

                return $result;
    } 

推荐答案

这行看起来不对:

getCats($row['parent_id'],$level+1);

您应该使用当前的子 ID 调用它 - 此时您会一遍又一遍地使用相同的 ID 调用它.像这样(您需要从表中选择 id):

You should be calling it with the current child ID - at the moment you're calling it with the same ID over and over. Something like this (you need to select the id from your table):

getCats($row['id'], $level + 1);

您需要更新查询以选择id:

you need to update your query to select id:

$query = "SELECT id, title, parent_id from t_cats where parent_id = '$parent' AND id != parent_id";

如果一个项目是它自己的父项，我还添加了一点来阻止它进入循环.

I've also added a bit to stop it getting into a loop if an item is its own parent.

这篇关于php无限循环的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！