CREATE TABLE Hierarchy
(Parent VARCHAR(20) NOT NULL,
Child VARCHAR(20),
CONSTRAINT UIX_ParentChild
UNIQUE NONCLUSTERED (Parent,Child))
CREATE CLUSTERED INDEX CIX_Parent
ON Hierarchy(Parent)
GO
INSERT Hierarchy VALUES('World','Europe')
INSERT Hierarchy VALUES('World','North America')
INSERT Hierarchy VALUES('Europe','France')
INSERT Hierarchy VALUES('France','Paris')
INSERT Hierarchy VALUES('North America','United States')
INSERT Hierarchy VALUES('North America','Canada')
INSERT Hierarchy VALUES('United States','New York')
INSERT Hierarchy VALUES('United States','Washington')
INSERT Hierarchy VALUES('New York','New York City')
INSERT Hierarchy VALUES('Washington','Redmond')
GO
此种表示方法不会清楚显示数据中暗含的结构。
Parent Child
---------------------------------- ----------------------------------
World Europe
World North America
Europe France
France Paris
North America United States
North America Canada
United States New York
United States Washington
New York New York City
Washington Redmond
而下例则更容易解释:
World
North America
Canada
United States
Washington
Redmond
New York
New York City
Europe
France
Paris
这个是表结构及效果。