Unlimited classification-summary

PHP code: // unlimited classification-path // principle: splits the path to obtain all desired PIDs and IDs. The path is a field in the design table, contains a series of IDs from the ancestor id to the parent id // this method, whether viewed or deleted, etc... syntaxHighlighter. all (); PHP code: // unlimited classification-path used // principle: all desired PIDs and IDs are obtained through Path splitting, A path is a field when designing a table. it contains a series of IDs from the ancestor id to the parent id. // this method, whether viewed or deleted, and other operations, you only need to execute an SQL statement once to achieve the desired results. // This method is also preferred, because my principle is that recursion is not used, instead of 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 (), concatenate 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 one point for The explode () function, no matter whether the string to be split contains any character that uses the parameter, at least one array containing an element $ count = count (explode ('-', $ row ['path']) is returned. -1; // str_repeat (), repeat the string mainly for the sake of clear format $ str = str_repeat ('', $ count); echo $ str. $ id. '=> '. $ row ['name'].' ';} /*********************************** Delete operation, the same path is used. for example, if you want to delete the Thunder classification, first find the path ************************ * ************* // * $ 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 with this category as the parent class or ancestor class $ new_path = $ path. '-'. $ id; // you can delete $ sql2 = "delete from wx_kind where id = {$ id} or path like '{$ New_path} %' "; $ result2 = mysql_query ($ sql2); if ($ result2 & mysql_affected_rows () {echo 'deleted successfully! ';} Else {echo' deletion failed! ';} *//************************************* *************** // Use recursive functions, I don't explain that much. let's look at the code directly. The main difference is that 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 deletion method is as follows, let's take a look at the sequence of deletion as described below. and where to delete the del_classify function ($ id) {// use recursion to find all sub-categories whose id is parent id or ancestor id, and then delete them from the inside out, note 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 );} // Delete $ sql1 = "delete from wx_kind where id = {$ id}" outside the loop, instead of any prompt $ 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' -- tables -- 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 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 ');