测试如下：
select @@version
Microsoft SQL Server 2008 R2 (RTM) - 10.50.1600.1 (X64)
Apr 2 2010 15:48:46
Copyright (c) Microsoft Corporation
Developer Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1) (Hypervisor)
--测试表建立
CREATE TABLE BaseTable
(PrimaryKey int PRIMARY KEY IDENTITY(1,1),
Color nvarchar(10) NOT NULL,
Material nvarchar(10) NOT NULL,
ComputedCol AS (Color + Material)
)
GO
--Create a view that contains all columns from the base table.
CREATE VIEW InsteadView
AS SELECT PrimaryKey, Color, Material, ComputedCol
FROM BaseTable
GO
--Create an INSTEAD OF INSERT trigger on the view.
CREATE TRIGGER InsteadTrigger on InsteadView
INSTEAD OF INSERT
AS
BEGIN
--Build an INSERT statement ignoring inserted.PrimaryKey and
--inserted.ComputedCol.
INSERT INTO BaseTable
SELECT Color, Material
FROM inserted
END
GO
插入数据测试
--直接引用 BaseTable 的 INSERT 语句无法为 PrimaryKey 列和 ComputedCol 列提供值。例如：
--A correct INSERT statement that skips the PrimaryKey and ComputedCol columns.
INSERT INTO BaseTable (Color, Material)
VALUES (N'Red', N'Cloth')
--View the results of the INSERT statement.
SELECT PrimaryKey, Color, Material, ComputedCol
FROM BaseTable
PrimaryKey Color Material ComputedCol
1 Red Cloth RedCloth
--下面语句返回错误，无法为计算列提供值，报错
--An incorrect statement that tries to supply a value for the
--PrimaryKey and ComputedCol columns.
INSERT INTO BaseTable(Color, Material,ComputedCol)
VALUES ( N'Green', N'Wood', N'GreenWood')
>[Error] Script lines: 40-42 ------------------------
不能修改列 "ComputedCol"，因为它是计算列，或者是 UNION 运算符的结果。
Msg: 271, Level: 16, State: 1, Procedure: , Line: 1
官方文档里提到下面的测试不对：
但是，引用 InsteadView 的 INSERT 语句必须为 PrimaryKey 列和 ComputedCol 列提供值：
--A correct INSERT statement supplying dummy values for the
--PrimaryKey and ComputedCol columns.
INSERT INTO InsteadView (PrimaryKey, Color, Material, ComputedCol)
VALUES (999, N'Blue', N'Plastic', N'XXXXXX')
--View the results of the INSERT statement.
SELECT PrimaryKey, Color, Material, ComputedCol
FROM InsteadView
传递到 InsteadTrigger 的所插入表是由不可为空值的 PrimaryKey 列和 ComputedCol 列生成的，因此引用该视图的 INSERT 语句必须为那些列提供值。值 999 和 N'XXXXXX' 将传递到 InsteadTrigger，但是触发器中的 INSERT 语句未选择 inserted.PrimaryKey 或 inserted.ComputedCol；因此，将忽略这两个值。实际插入到 BaseTable 的行在 PrimaryKey 中的值为 2，在 ComputedCol 中的值为 N'BluePlastic'。
但是实际结果是测试通过的，无需指定 PrimaryKey 列和 ComputedCol 列，如下：
--下面没有提供值，报错
INSERT INTO InsteadView (Color, Material)
VALUES (N'Yellow', N'Video')
SELECT PrimaryKey, Color, Material, ComputedCol
FROM InsteadView
PrimaryKey Color Material ComputedCol
1 Red Cloth RedCloth
2 Blue Plastic BluePlastic
3 Yellow Video YellowVideo
