Unlimited classification-summary _ PHP Tutorial

Unlimited category-summary. PHP code part: unlimited classification-path principle: all desired PIDs and IDs are obtained through Path splitting. The path is a field during table design, contains the PHP code part from the ancestor:

// Unlimited classification-path used

// Principle: all desired PIDs and IDs are obtained through Path splitting. The path is a field in the design table and contains a series of IDs from the ancestor id to the parent id.

// This method can achieve the desired effect by executing an SQL statement once, regardless of viewing or deleting other operations.

// This method is also my favorite one, because my principle is that we can never use recursion without recursion.

$ Link = mysql_connect ('localhost', 'username, 'password ');

If (mysql_errno ()){

Echo 'database connection failed: '. mysql_error ();

}

Mysql_select_db ('Db _ kind ');

Mysql_set_charset ('utf8 ');

// Concat (), concatenates a string into a new string

// The following code completes an infinite classification reality

$ SQL = "select concat (path, '-', id) as conpath, id, name, path from wx_kind order by conpath ";

$ Result = mysql_query ($ SQL );

While ($ row = mysql_fetch_assoc ($ result )){

$ Arr = array ();

// You can select the path field or the new conpath field to split the string.

// Note That The explode () function returns an array containing at least one element no matter whether the string to be split contains characters using parameters.

$ Count = count (explode ('-', $ row ['path'])-1;

// Str_repeat (), repeat the string mainly for clear format

$ Str = str_repeat ('', $ count );

Echo $ str. $ id. '=>'. $ row ['name'].'

';

}

/***********************************

If you want to delete a file, use the same path.

For example, you want to delete the Thunder classification.

First, find the path based on its id

**************************************/

/* $ Sql1 = "select id, path from wx_kind where id = 20 ";

$ Result1 = mysql_query ($ sql1 );

$ Row = mysql_fetch_assoc ($ result1 );

$ Id = $ row ['id'];

$ Path = $ row ['path'];

// Construct all paths that use this category as the parent class or ancestor class

$ New_path = $ path. '-'. $ id;

// The deletion operation can be performed below.

$ Sql2 = "delete from wx_kind where id = {$ id} or path like '{$ new_path} % '";

$ Result2 = mysql_query ($ sql2 );

If ($ result2 & mysql_affected_rows ()){

Echo 'deleted! ';

} Else {

Echo 'deletion failed! ';

}*/

/*************************************** **************/

// The method for using recursive functions is not explained as much. let's look at the code directly, mainly because the searching method is different.

Function display_classify ($ pid = 0, $ num = 0 ){

$ SQL = "select id, name from wx_kind where pid = {$ pid }";

$ Result = mysql_query ($ SQL );

While ($ row = mysql_fetch_assoc ($ result )){

$ Id = $ row ['id'];

$ Str = str_repeat ('', $ num );

Echo $ str. $ id. '=>'. $ row ['name'].'

';

Display_classify ($ id, $ num + 1, $ sid );

}

}

// Display_classify ();

/*************************************** **************/

// The following is the deletion method. Take a look at the order of the deletion as described below, and pay attention to where to delete the deletion.

Function del_classify ($ id ){

// Use recursion to find all sub-categories whose id is parent id or ancestor id, and then delete them from the inside out to the outside. pay attention to the order of deletion.

$ SQL = "select id, name from wx_kind where pid = {$ id }";

$ Result = mysql_query ($ SQL );

While ($ row = mysql_fetch_assoc ($ result )){

$ Id = $ row ['id'];

Del_classify ($ id );

}

// The delete operation is performed out of the loop.

$ Sql1 = "delete from wx_kind where id = {$ id }";

// Delete the file directly, instead of any prompts.

$ Result = mysql_query ($ sql1 );

If (! ($ Result & mysql_affected_rows ())){

$ Bool = false;

} Else {

$ Bool = true;

}

Return $ bool;

}

// Del_classify (5 );

The following is the database code:

--

-- Database: 'DB _ kind'

--

----------------------------------------------------------

--

-- Table structure 'wx _ kind_dump'

--

Create table 'wx _ kind_dump '(

'Id' int (11) not null auto_increment,

'Pid 'int (11) not null,

'Name' char (40) not null,

'Path' char (40) not null,

Primary key ('id ')

) ENGINE = MyISAM default charset = utf8 AUTO_INCREMENT = 26;

--

-- Export the table data 'wx _ kind_dump'

--

Insert into 'wx _ kind_dump 'VALUES (1, 0, 'news', '0 ');

Insert into 'wx _ kind_dump 'values (2, 0, 'video', '0 ');

Insert into 'wx _ kind_dump 'VALUES (3, 0, 'Image', '0 ');

Insert into 'wx _ kind_dump 'values (4, 0, 'reading', '0 ');

Insert into 'wx _ kind_dump 'VALUES (5, 1, 'political News', '0-1 ');

Insert into 'wx _ kind_dump 'VALUES (6, 1, 'financial News', '0-1 ');

Insert into 'wx _ kind_dump 'VALUES (7, 1, 'Entertainment News', '0-1 ');

Insert into 'wx _ kind_dump 'VALUES (8, 1, 'Sports News', '0-1 ');

Insert into 'wx _ kind_dump 'VALUES (9, 8, 'basketball', '0-1-8 ');

Insert into 'wx _ kind_dump 'VALUES (10, 8, 'soccer', '0-1-8 ');

Insert into 'wx _ kind_dump 'values (11, 8, 'F1', '0-1-8 ');

Insert into 'wx _ kind_dump 'VALUES (12, 8, 'Tennis', '0-1-8 ');

Insert into 'wx _ kind_dump 'VALUES (13, 9, 'International basketball', '0-1-8-9 ');

Insert into 'wx _ kind_dump 'values (14, 9, 'CBA', '0-1-8-9 ');

Insert into 'wx _ kind_dump 'values (15, 9, 'Cuba ', '0-1-8-9 ');

Insert into 'wx _ kind_dump 'VALUES (16, 9, 'NBA', '0-1-8-9 ');

Insert into 'wx _ kind_dump 'values (17, 9, 'NCAA ', '0-1-8-9 ');

Insert into 'wx _ kind_dump 'VALUES (18, 16, 'Hot heat', '0-1-8-9-16 ');

Insert into 'wx _ kind_dump 'VALUES (19, 16, 'Lakers', '0-1-8-9-16 ');

Insert into 'wx _ kind_dump 'values (20, 16, 'Thunder', '0-1-8-9-16 ');

Insert into 'wx _ kind_dump 'VALUES (21, 16, 'Celt', '0-1-8-9-16 ');

Insert into 'wx _ kind_dump 'values (22, 18, 'James ', '0-1-8-9-16-18 ');

Insert into 'wx _ kind_dump 'values (23, 18, 'Wade ', '0-1-8-9-16-18 ');

Insert into 'wx _ kind_dump 'values (24, 20, 'kd ', '0-1-8-9-16-20 ');

Insert into 'wx _ kind_dump 'values (25, 20, 'Ws ', '0-1-8-9-16-20 ');

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