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database-design - 表示数据库中的产品分类

转载 作者:行者123 更新时间:2023-12-02 15:41:35 25 4
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我必须在数据库中表示具有父子关系的复杂产品分类。有人可以指导我这样做吗??

例如根可能是“所有产品”然后可能在第二层我们有“电脑”和“家具”像一棵树??

最佳答案

这是一个使用 SQL Server 2005 的简单树示例:

--go through a nested table supervisor - user table and display the chain
DECLARE @Contacts table (id varchar(6), first_name varchar(10), reports_to_id varchar(6))
INSERT @Contacts VALUES ('1','Jerome', NULL ) -- tree is as follows:
INSERT @Contacts VALUES ('2','Joe' ,'1') -- 1-Jerome
INSERT @Contacts VALUES ('3','Paul' ,'2') -- / \
INSERT @Contacts VALUES ('4','Jack' ,'3') -- 2-Joe 9-Bill
INSERT @Contacts VALUES ('5','Daniel','3') -- / \ \
INSERT @Contacts VALUES ('6','David' ,'2') -- 3-Paul 6-David 10-Sam
INSERT @Contacts VALUES ('7','Ian' ,'6') -- / \ / \
INSERT @Contacts VALUES ('8','Helen' ,'6') -- 4-Jack 5-Daniel 7-Ian 8-Helen
INSERT @Contacts VALUES ('9','Bill ' ,'1') --
INSERT @Contacts VALUES ('10','Sam' ,'9') --

DECLARE @Root_id char(4)

--get 2 and below
SET @Root_id=2
PRINT '@Root_id='+COALESCE(''''+@Root_id+'''','null')
;WITH StaffTree AS
(
SELECT
c.id, c.first_name, c.reports_to_id, c.reports_to_id as Manager_id, cc.first_name AS Manager_first_name, 1 AS LevelOf
FROM @Contacts c
LEFT OUTER JOIN @Contacts cc ON c.reports_to_id=cc.id
WHERE c.id=@Root_id OR (@Root_id IS NULL AND c.reports_to_id IS NULL)
UNION ALL
SELECT
s.id, s.first_name, s.reports_to_id, t.id, t.first_name, t.LevelOf+1
FROM StaffTree t
INNER JOIN @Contacts s ON t.id=s.reports_to_id
WHERE s.reports_to_id=@Root_id OR @Root_id IS NULL OR t.LevelOf>1
)
SELECT * FROM StaffTree

输出:

@Root_id='2   '
id first_name reports_to_id Manager_id Manager_first_name LevelOf
------ ---------- ------------- ---------- ------------------ -----------
2 Joe 1 1 Jerome 1
3 Paul 2 2 Joe 2
6 David 2 2 Joe 2
7 Ian 6 6 David 3
8 Helen 6 6 David 3
4 Jack 3 3 Paul 3
5 Daniel 3 3 Paul 3

(7 row(s) affected)

更改@Root_id 以获得不同的输出:

@Root_id=null
id first_name reports_to_id Manager_id Manager_first_name LevelOf
------ ---------- ------------- ---------- ------------------ -----------
1 Jerome NULL NULL NULL 1
2 Joe 1 1 Jerome 2
9 Bill 1 1 Jerome 2
10 Sam 9 9 Bill 3
3 Paul 2 2 Joe 3
6 David 2 2 Joe 3
7 Ian 6 6 David 4
8 Helen 6 6 David 4
4 Jack 3 3 Paul 4
5 Daniel 3 3 Paul 4

(10 row(s) affected)

关于database-design - 表示数据库中的产品分类,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4335971/

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