[MySQL] 实现树形的遍历（关于多级菜单栏以及多级

和通数据库htsjk.Com2019-03-07 21:14 来源:未知阅读:16372 评论 499 热度3

标签：递归

[MySQL] 实现树形的遍历（关于多级菜单栏以及多级上下部门的查询问题），mysql树形

前言：
        关于多级别菜单栏或者权限系统中部门上下级的树形遍历，oracle中有connect by来实现，mysql没有这样的便捷途径，所以MySQL遍历数据表是我们经常会遇到的头痛问题，下面通过存储过程来实现。

1，建立测试表和数据：
DROP TABLE IF EXISTS csdn.channel;
CREATE TABLE csdn.channel (
id INT(11) NOT NULL AUTO_INCREMENT,
cname VARCHAR(200) DEFAULT NULL,
parent_id INT(11) DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO channel(id,cname,parent_id)
VALUES (13,'首页',-1),
(14,'TV580',-1),
(15,'生活580',-1),
(16,'左上幻灯片',13),
(17,'帮忙',14),
(18,'栏目简介',17);
DROP TABLE IF EXISTS channel;

2，利用临时表和递归过程实现树的遍历（mysql的UDF不能递归调用）：

2.1，从某节点向下遍历子节点，递归生成临时表数据
-- pro_cre_childlist
DELIMITER $$
DROP PROCEDURE IF EXISTS csdn.pro_cre_childlist$$
CREATE PROCEDURE csdn.pro_cre_childlist(IN rootId INT,IN nDepth INT)
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE b INT;
DECLARE cur1 CURSOR FOR SELECT id FROM channel WHERE parent_id=rootId;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
SET max_sp_recursion_depth=12;

INSERT INTO tmpLst VALUES (NULL,rootId,nDepth);

OPEN cur1;

FETCH cur1 INTO b;
WHILE done=0 DO
CALL pro_cre_childlist(b,nDepth+1);
FETCH cur1 INTO b;
END WHILE;

CLOSE cur1;
END$$

2.2，从某节点向上追溯根节点，递归生成临时表数据
-- pro_cre_parentlist
DELIMITER $$
DROP PROCEDURE IF EXISTS csdn.pro_cre_parentlist$$
CREATE PROCEDURE csdn.pro_cre_parentlist(IN rootId INT,IN nDepth INT)
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE b INT;
DECLARE cur1 CURSOR FOR SELECT parent_id FROM channel WHERE id=rootId;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
SET max_sp_recursion_depth=12;

INSERT INTO tmpLst VALUES (NULL,rootId,nDepth);

OPEN cur1;

FETCH cur1 INTO b;
WHILE done=0 DO
CALL pro_cre_parentlist(b,nDepth+1);
FETCH cur1 INTO b;
END WHILE;

CLOSE cur1;
END$$


2.3，实现类似Oracle SYS_CONNECT_BY_PATH的功能，递归过程输出某节点id路径
-- pro_cre_pathlist
DELIMITER $$
USE csdn$$
DROP PROCEDURE IF EXISTS pro_cre_pathlist$$
CREATE PROCEDURE pro_cre_pathlist(IN nid INT,IN delimit VARCHAR(10),INOUT pathstr VARCHAR(1000))
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE parentid INT DEFAULT 0;
DECLARE cur1 CURSOR FOR
SELECT t.parent_id,CONCAT(CAST(t.parent_id AS CHAR),delimit,pathstr)
FROM channel AS t WHERE t.id = nid;

DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
SET max_sp_recursion_depth=12;

OPEN cur1;

FETCH cur1 INTO parentid,pathstr;
WHILE done=0 DO
CALL pro_cre_pathlist(parentid,delimit,pathstr);
FETCH cur1 INTO parentid,pathstr;
END WHILE;

CLOSE cur1;
END$$

DELIMITER ;

2.4，递归过程输出某节点name路径
-- pro_cre_pnlist
DELIMITER $$
USE csdn$$
DROP PROCEDURE IF EXISTS pro_cre_pnlist$$
CREATE PROCEDURE pro_cre_pnlist(IN nid INT,IN delimit VARCHAR(10),INOUT pathstr VARCHAR(1000))
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE parentid INT DEFAULT 0;
DECLARE cur1 CURSOR FOR
SELECT t.parent_id,CONCAT(t.cname,delimit,pathstr)
FROM channel AS t WHERE t.id = nid;

DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
SET max_sp_recursion_depth=12;

OPEN cur1;

FETCH cur1 INTO parentid,pathstr;
WHILE done=0 DO
CALL pro_cre_pnlist(parentid,delimit,pathstr);
FETCH cur1 INTO parentid,pathstr;
END WHILE;

CLOSE cur1;
END$$

DELIMITER ;

2.5，调用函数输出id路径
-- fn_tree_path
DELIMITER $$
DROP FUNCTION IF EXISTS csdn.fn_tree_path$$
CREATE FUNCTION csdn.fn_tree_path(nid INT,delimit VARCHAR(10)) RETURNS VARCHAR(2000) CHARSET utf8
BEGIN
DECLARE pathid VARCHAR(1000);

SET @pathid=CAST(nid AS CHAR);
CALL pro_cre_pathlist(nid,delimit,@pathid);

RETURN @pathid;
END$$


2.6，调用函数输出name路径
-- fn_tree_pathname
-- 调用函数输出name路径
DELIMITER $$
DROP FUNCTION IF EXISTS csdn.fn_tree_pathname$$
CREATE FUNCTION csdn.fn_tree_pathname(nid INT,delimit VARCHAR(10)) RETURNS VARCHAR(2000) CHARSET utf8
BEGIN
DECLARE pathid VARCHAR(1000);
SET @pathid='';
CALL pro_cre_pnlist(nid,delimit,@pathid);
RETURN @pathid;
END$$
DELIMITER ;

2.7，调用过程输出子节点
-- pro_show_childLst
DELIMITER $$
-- 调用过程输出子节点
DROP PROCEDURE IF EXISTS pro_show_childLst$$
CREATE PROCEDURE pro_show_childLst(IN rootId INT)
BEGIN
DROP TEMPORARY TABLE IF EXISTS tmpLst;
CREATE TEMPORARY TABLE IF NOT EXISTS tmpLst
(sno INT PRIMARY KEY AUTO_INCREMENT,id INT,depth INT);

CALL pro_cre_childlist(rootId,0);

SELECT channel.id,CONCAT(SPACE(tmpLst.depth*2),'--',channel.cname) NAME,channel.parent_id,tmpLst.depth,fn_tree_path(channel.id,'/') path,fn_tree_pathname(channel.id,'/') pathname
FROM tmpLst,channel WHERE tmpLst.id=channel.id ORDER BY tmpLst.sno;
END$$

2.8，调用过程输出父节点
-- pro_show_parentLst
DELIMITER $$
-- 调用过程输出父节点
DROP PROCEDURE IF EXISTS `pro_show_parentLst`$$
CREATE PROCEDURE `pro_show_parentLst`(IN rootId INT)
BEGIN
DROP TEMPORARY TABLE IF EXISTS tmpLst;
CREATE TEMPORARY TABLE IF NOT EXISTS tmpLst
(sno INT PRIMARY KEY AUTO_INCREMENT,id INT,depth INT);

CALL pro_cre_parentlist(rootId,0);
SELECT channel.id,CONCAT(SPACE(tmpLst.depth*2),'--',channel.cname) NAME,channel.parent_id,tmpLst.depth,fn_tree_path(channel.id,'/') path,fn_tree_pathname(channel.id,'/') pathname
FROM tmpLst,channel WHERE tmpLst.id=channel.id ORDER BY tmpLst.sno;
END$$

3，开始测试：
3.1，从根节点开始显示，显示子节点集合：
mysql> CALL pro_show_childLst(-1);
+----+-----------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+-----------------------+-----------+-------+-------------+----------------------------+
| 13 | --首页 | -1 | 1 | -1/13 | 首页/ |
| 16 | --左上幻灯片 | 13 | 2 | -1/13/16 | 首页/左上幻灯片/ |
| 14 | --TV580 | -1 | 1 | -1/14 | TV580/ |
| 17 | --帮忙 | 14 | 2 | -1/14/17 | TV580/帮忙/ |
| 18 | --栏目简介 | 17 | 3 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
| 15 | --生活580 | -1 | 1 | -1/15 | 生活580/ |
+----+-----------------------+-----------+-------+-------------+----------------------------+
6 rows in set (0.05 sec)

Query OK, 0 rows affected (0.05 sec)

3.2，显示首页下面的子节点
CALL pro_show_childLst(13);
mysql> CALL pro_show_childLst(13);
+----+---------------------+-----------+-------+----------+-------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+---------------------+-----------+-------+----------+-------------------------+
| 13 | --首页 | -1 | 0 | -1/13 | 首页/ |
| 16 | --左上幻灯片 | 13 | 1 | -1/13/16 | 首页/左上幻灯片/ |
+----+---------------------+-----------+-------+----------+-------------------------+
2 rows in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)

mysql>

3.3，显示TV580下面的所有子节点
CALL pro_show_childLst(14);
mysql> CALL pro_show_childLst(14);
+----+--------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+--------------------+-----------+-------+-------------+----------------------------+
| 14 | --TV580 | -1 | 0 | -1/14 | TV580/ |
| 17 | --帮忙 | 14 | 1 | -1/14/17 | TV580/帮忙/ |
| 18 | --栏目简介 | 17 | 2 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
+----+--------------------+-----------+-------+-------------+----------------------------+
3 rows in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)

mysql>

3.4，“帮忙”节点有一个子节点，显示出来：
CALL pro_show_childLst(17);
mysql> CALL pro_show_childLst(17);
+----+------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+------------------+-----------+-------+-------------+----------------------------+
| 17 | --帮忙 | 14 | 0 | -1/14/17 | TV580/帮忙/ |
| 18 | --栏目简介 | 17 | 1 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
+----+------------------+-----------+-------+-------------+----------------------------+
2 rows in set (0.03 sec)

Query OK, 0 rows affected (0.03 sec)

mysql>

3.5，“栏目简介”没有子节点，所以只显示最终节点：
mysql> CALL pro_show_childLst(18);
+----+----------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+----------------+-----------+-------+-------------+----------------------------+
| 18 | --栏目简介 | 17 | 0 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
+----+----------------+-----------+-------+-------------+----------------------------+
1 row in set (0.36 sec)

Query OK, 0 rows affected (0.36 sec)

mysql>

3.6，显示根节点的父节点
CALL pro_show_parentLst(-1);
mysql> CALL pro_show_parentLst(-1);
Empty set (0.01 sec)

Query OK, 0 rows affected (0.01 sec)

mysql>

3.7，显示“首页”的父节点
CALL pro_show_parentLst(13);
mysql> CALL pro_show_parentLst(13);
+----+----------+-----------+-------+-------+----------+
| id | NAME | parent_id | depth | path | pathname |
+----+----------+-----------+-------+-------+----------+
| 13 | --首页 | -1 | 0 | -1/13 | 首页/ |
+----+----------+-----------+-------+-------+----------+
1 row in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)

mysql>

3.8，显示“TV580”的父节点，parent_id为-1
CALL pro_show_parentLst(14);
mysql> CALL pro_show_parentLst(14);
+----+---------+-----------+-------+-------+----------+
| id | NAME | parent_id | depth | path | pathname |
+----+---------+-----------+-------+-------+----------+
| 14 | --TV580 | -1 | 0 | -1/14 | TV580/ |
+----+---------+-----------+-------+-------+----------+
1 row in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)

3.9，显示“帮忙”节点的父节点
mysql>
CALL pro_show_parentLst(17);
mysql> CALL pro_show_parentLst(17);
+----+-----------+-----------+-------+----------+---------------+
| id | NAME | parent_id | depth | path | pathname |
+----+-----------+-----------+-------+----------+---------------+
| 17 | --帮忙 | 14 | 0 | -1/14/17 | TV580/帮忙/ |
| 14 | --TV580 | -1 | 1 | -1/14 | TV580/ |
+----+-----------+-----------+-------+----------+---------------+
2 rows in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)

mysql>

3.10，显示最低层节点“栏目简介”的父节点
CALL pro_show_parentLst(18);
mysql> CALL pro_show_parentLst(18);
+----+----------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+----------------+-----------+-------+-------------+----------------------------+
| 18 | --栏目简介 | 17 | 0 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
| 17 | --帮忙 | 14 | 1 | -1/14/17 | TV580/帮忙/ |
| 14 | --TV580 | -1 | 2 | -1/14 | TV580/ |
+----+----------------+-----------+-------+-------------+----------------------------+
3 rows in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)

mysql>

参考网址：
http://jan.kneschke.de/projects/mysql/sp/sp_tree.sql
http://blog.csdn.net/ylqmf/article/details/5172901

1）问题描述：在主程序中提供下列菜单： 1…建立树 2…前序遍历树 3…中序(非递归)遍历树 4…后序遍历树 0

/*广义表建立二叉树和遍历二叉树*/

#include <stdio.h>
#include <stdlib.h>

#define MaxSize 100

typedef struct node
{
char data;
struct node *lchild;
struct node *rchild;
}BTNode,*BiTree;

void creategeneralizelist(BiTree *b,char *str)
{
BTNode *St[MaxSize],*p=NULL;
int top=-1,flag,j;
char ch;
for(j=0;(ch=str[j])!='#';j++)
{
switch(ch)
{
case '(':
top++;
St[top]=p;
flag=1;
break;

case ')':
top--;
break;

case ',':
flag=2;
break;

default:
p=(BiTree)malloc(sizeof(BTNode));
p->data=ch;
p->lchild=NULL;
p->rchild=NULL;
if(*b==NULL)
*b=p;
else
{
switch(flag)
{
case 1:
St[top]->lchild=p;
break;

case 2:
St[top]->rchild=p;
break;
}
}
}
}
}

void PreOrder(BiTree T)
{
if(T)
{
printf("%2c",T->data);
PreOrder(T->lchild);
PreOrder(T->rchild);
}
printf("\n");
}

void InOrder(B......余下全文>>

java递归遍历某个菜单下的菜单树

不太清楚你这个Menu是哪来的类，不过如果上文你的程序能执行的话，说明menu.getChilds()是个集合，应该带有size()的函数。你可以取出menu.getChilds()的大小，再从头到尾遍历它。

int count=menu.getChilds().size();

for(int i=0;i<count;i++)
{
showMenu( ((Menu)menu.getChilds().get(i)) , 0 );
//我估计这些children是个list，可以顺序遍历；但也有
//部分可能是set,那样就得用iterator了。
}

本站文章为和通数据库网友分享或者投稿，欢迎任何形式的转载，但请务必注明出处.
同时文章内容如有侵犯了您的权益，请联系QQ：970679559，我们会在尽快处理。

返回首页

暂无相关文章

评论暂时关闭