本人目前的项目是微信公众号的一个小型电商系统,需要将邀请好友模块优化成5级分销流程,参考此文章,我选用【闭包表】模式,树形结构数据存储方案全部介绍见另一篇文章。待本人项目完成奉上自己的项目流程及数据库设计。
将Closure Table翻译成闭包表不知道是否合适,闭包表的思路和物化路径差不多,都是空间换时间,Closure Table,一种更为彻底的全路径结构,分别记录路径上相关结点的全展开形式。能明晰任意两结点关系而无须多余查询,级联删除和结点移动也很方便。但是它的存储开销会大一些,除了表示结点的Meta信息,还需要一张专用的关系表。
以下图举例数据举例:
创建主表:
1 2 3 4 5 | CREATE TABLE nodeInfo ( node_id INT NOT NULL AUTO_INCREMENT, node_name VARCHAR (255), PRIMARY KEY (`node_id`) ) DEFAULT CHARSET = utf8; |
创建关系表:
1 2 3 4 5 6 | CREATE TABLE nodeRelationship ( ancestor INT NOT NULL, descendant INT NOT NULL, distance INT NOT NULL, PRIMARY KEY (ancestor, descendant) ) DEFAULT CHARSET = utf8; |
其中
- Ancestor代表祖先节点
- Descendant代表后代节点
- Distance 祖先距离后代的距离
添加数据(创建存储过程)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | CREATE DEFINER = `root`@`localhost` PROCEDURE `AddNode`(`_parent_name` varchar(255),`_node_name` varchar(255)) BEGIN DECLARE _ancestor INT; DECLARE _descendant INT; DECLARE _parent INT; IF NOT EXISTS(SELECT node_id From nodeinfo WHERE node_name = _node_name) THEN INSERT INTO nodeinfo (node_name) VALUES(_node_name); SET _descendant = (SELECT node_id FROM nodeinfo WHERE node_name = _node_name); INSERT INTO noderelationship (ancestor,descendant,distance) VALUES(_descendant,_descendant,0); IF EXISTS (SELECT node_id FROM nodeinfo WHERE node_name = _parent_name) THEN SET _parent = (SELECT node_id FROM nodeinfo WHERE node_name = _parent_name); INSERT INTO noderelationship (ancestor,descendant,distance) SELECT ancestor,_descendant,distance+1 from noderelationship where descendant = _parent; END IF; END IF; END; |
完成后2张表的数据大致是这样的:(注意:每个节点都有一条到其本身的记录。)
查询Fruit下所有的子节点:
1 2 3 4 5 6 7 8 9 | SELECT n3.node_name FROM nodeinfo n1 INNER JOIN noderelationship n2 ON n1.node_id = n2.ancestor INNER JOIN nodeinfo n3 ON n2.descendant = n3.node_id WHERE n1.node_name = 'Fruit' AND n2.distance != 0 |
查询Fruit下直属子节点:
1 2 3 4 5 6 7 8 9 | SELECT n3.node_name FROM nodeinfo n1 INNER JOIN noderelationship n2 ON n1.node_id = n2.ancestor INNER JOIN nodeinfo n3 ON n2.descendant = n3.node_id WHERE n1.node_name = 'Fruit' AND n2.distance = 1 |
查询Fruit所处的层级:
1 2 3 4 5 6 7 8 9 10 | SELECT n2.*, n3.node_name FROM nodeinfo n1 INNER JOIN noderelationship n2 ON n1.node_id = n2.descendant INNER JOIN nodeinfo n3 ON n2.ancestor = n3.node_id WHERE n1.node_name = 'Fruit' ORDER BY n2.distance DESC |
另外要删除节点也非常的简单,这里就不再做过多的阐述。
转自https://www.biaodianfu.com/closure-table.html