Share a PHP code to implement infinite classification program_PHP tutorial

Infinite classification is a problem encountered in all program development. Now I will introduce an infinite classification program implemented by php+mysql. Friends in need can refer to it.

Let me show you my database structure: The name of the database is: fa_category

Field	Type	Comment
cid	int(11)	分类id
catename	varchar(255)	分类名字
catetype	int(1)	分类类型，1为单页面，2为普通分类
catdir	varchar(255)	英文目录
display	int(1)	1为显示，2为不显示
keywords	varchar(255)	栏目关键字
description	text	栏目描述
ctime	int(11)	创建时间
parentid	int(11)	父节点id，最高节点父节点为0

We use a parentid field to record the id of the parent node. If parentid is 0, it is root. Without further ado, let’s see how to write the code. The function we want to achieve is as shown in the picture:

                                                                                    How to display it like this? I have been thinking about this question for a long time. Let’s take a look at this SQL statement first,

The code is as follows	Copy code
SELECT c.cat_id, c.cat_name, c.measure_unit, c.parent_id, c.is_show, c.show_in_nav, c.grade ,c.sort_order, COUNT( s.cat_id ) AS has_children FROM ecs_category AS c LEFT JOIN ecs_category AS s ON s.parent_id = c.cat_id GROUP BY c.cat_id ORDER BY c.parent_id, c.sort_order ASC

Use a left join to connect a table and return a field has_children. This field records how many child nodes there are.

Let’s take a look at the code,

代码如下

复制代码

public function getCategory($catid=0,$re_type = true,$selected=0)     {         $db      =  new Public_DataBase();         $sql  =  'select c.cid,c.catename,c.catetype,c.ctime,c.parentid,count(s.cid) as has_children from '.         __MYSQL_PRE.'category as c left join '.         __MYSQL_PRE.'category as s on s.parentid=c.cid group by c.cid order by c.parentid asc';         $res          =  $db->selectTable($sql);         $cateInfo     =    self::getChildTree($catid,$res);         if($re_type==true)         {                $select   =    '';               foreach($cateInfo as $val)               {                  $select .= '                  $select .= ($selected == $val['cid']) ? "selected='ture'" : '';                  $select .= '>';                   if($val['level']>0)                   {                             $select .= str_repeat(' ', $val['level'] * 4);                   }                   $select .= htmlspecialchars(addslashes($val['catename']), ENT_QUOTES) . '';               }               return $select;         }                 else         {             foreach($cateInfo as $key=>$val)             {                   if($val['level']>0)                   {                                     $cateInfo[$key]['catename']    =    "|".str_repeat(' ', $val['level'] * 8)."└─".$val['catename'];                                             }             }             return $cateInfo;         }                     }         /**      * 通过父ID递归得到所有子节点树      * @param int $catid  上级分类      * @param array $arr  含有所有分类的数组      * @return array      */     public function getChildTree($catid,$arr)     {         $level = $last_cat_id = 0;         while (!empty($arr))         {             foreach($arr as $key=>$value)             {                 $cid     =  $value['cid'];                 if ($level == 0 && $last_cat_id == 0)                 {                    if ($value['parentid'] > 0)                    {                        break;                    }                    $options[$cid]          =     $value;                    $options[$cid]['level'] =     $level;                    $options[$cid]['id']    =     $cid;                    $options[$cid]['name']  =     $value['catename'];                    unset($arr[$key]);                    if ($value['has_children'] == 0)                    {                         continue;                    }                    $last_cat_id  = $cid;                    $cat_id_array = array($cid);                    $level_array[$last_cat_id] = ++$level;                    continue;                      }                 if ($value['parentid'] == $last_cat_id)                 {                         $options[$cid]          = $value;                         $options[$cid]['level'] = $level;                         $options[$cid]['id']    = $cid;                         $options[$cid]['name']  = $value['catename'];                         unset($arr[$key]);                         if ($value['has_children'] > 0)                         {                             if (end($cat_id_array) != $last_cat_id)                             {                                 $cat_id_array[] = $last_cat_id;                             }                                 $last_cat_id    = $cid;                                 $cat_id_array[] = $cid;                                 $level_array[$last_cat_id] = ++$level;                         }                 }                 elseif ($value['parentid'] > $last_cat_id)                 {                     break;                 }             }                          $count = count($cat_id_array);              if ($count > 1)              {                  $last_cat_id = array_pop($cat_id_array);                               }              elseif ($count == 1)              {                if ($last_cat_id != end($cat_id_array))                {                    $last_cat_id = end($cat_id_array);                }                else                {                     $level = 0;                     $last_cat_id = 0;                     $cat_id_array = array();                     continue;                }              }              if ($last_cat_id && isset($level_array[$last_cat_id]))                  {                    $level = $level_array[$last_cat_id];             }             else                  { $level = 0;             } }                                                           return $options;

}Use a smarty loop to display it. The effect is the same as the picture above! If you have any questions, please leave me a message.

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