Solutions for writing small functions

For a small function, there is a classification table calssID ----- unique identifier pid ----- parent IDname ----- name path ----- path CREATETABLE 'calss' (& nbsp; 'id' int (11) NOTNULLAUTO_INCREMENT, write a small function
There is a classification table calss

ID ----- unique ID
Pid ----- parent ID
Name ----- name
Path ----- path

Create table 'calls '(
'Id' int (11) not null AUTO_INCREMENT,
'Pid 'int (11) not null default '0 ',
'Name' varchar (32) not null,
'Path' varchar (32) not null,
Primary key ('id ')
) ENGINE = InnoDB AUTO_INCREMENT = 10 default charset = utf8;



How to write a path

For example, the data is as follows:

Insert into calss VALUES ('1', '0', 'Web developer', WEB );
Insert into calss VALUES ('2', '1', 'backbackend ', control );
Insert into calss VALUES ('3', '2', 'linguistic ', language );
Insert into calss VALUES ('4', '2', 'database', data );
Insert into calss VALUES ('5', '3', 'php', php );
Insert into calss VALUES ('6', '3', 'JSP ', jsp );
Insert into calss VALUES ('7', '3', 'asp ', asp );
Insert into calss VALUES ('8', '0', 'mobile app developing', phone );
Insert into calss VALUES ('9', '8', 'iOS ', ios );

Find the path of the php category
The final result is in the following format:
$ Php_path = "web/control/language/php /";


I am grateful for trying to implement a specific php code. it is said that the recursive idea is used. I have read the recursion idea for a day.

Can it be implemented without recursion? please help me understand every sentence of code comments with recursion. thank you very much.


Last sentence, Hello, girl, Hello

------ Solution --------------------
It can be obtained using the cyclic SQL statement they described.

You can also write it at will. you can understand it and change it again.

PHP code

// SELECT id, pid, path FROM calss; obtain the dataset and combine it into the following array $ array = array ('1' => 0, '2' => 1, '3' => 2, '4' => 2, '5' => 3, '6' => 3, '7' => 3, '8' => 0, '9' => 8); $ pathArray = array (1 => 'web', 2 => 'control ', 3 => 'language', 4 => 'Data', 5 => 'php', 6 => 'JSP ', 7 => 'asp ', 8 => 'phone', 9 => 'iOS '); // obtain the id list $ idArry = array (); getTopID (5, $ array ); // echo listPath (5, $ idArr, $ pathArray), "\ n"; unset ($ idArr); getTopID (6, $ array ); echo listpath (6, $ idArr, $ pathArray), "\ n"; unset ($ idArr); getTopID (8, $ array); echo listpath (8, $ idArr, $ pathArray), "\ n"; unset ($ idArr); getTopID (9, $ array); echo listpath (9, $ idArr, $ pathArray), "\ n "; unset ($ idArr); // function/*** obtain the upper-level Id array * @ param $ id * @ param $ array * @ return array */function getTopID ($ id, $ array) {global $ idArr; if (isset ($ array [$ id]) {$ idArr [] = $ array [$ id]; getTopID ($ array [$ id], $ array );}} /*** sort the result by the parent ID array * @ param $ id * @ param $ list * @ param $ array * @ return string */function listPath ($ id, $ list, $ array) {$ path = ''; array_push ($ list, $ id); sort ($ list); foreach ($ list as $ value) {if (isset ($ array [$ value]) {$ path. = $ array [$ value]. '/';} return $ path ;}