Tuesday, February 14, 2012

Concept for View

Hi,
Could someone please explain to me when the view is updatable and when it
is not? I am under the impression that if the two tables are joined togethe
r
in the view, then the view is not updatable... is it correct?
ThanksSee the CREATE VIEW in the Books Online <tsqlref.chm::/ts_create2_30hj.htm>
for a detailed description of when a view is updatable.
For an updatable view containing joins, INSERT/UPDATE/DELETE statements are
allowed as long as only one underlying base table is affected. For example:
CREATE TABLE Table1
(
Col1a int NOT NULL
CONSTRAINT PK_Table1 PRIMARY KEY,
Col1b int NOT NULL
)
GO
CREATE TABLE Table2
(
Col2a int NOT NULL
CONSTRAINT PK_Table2 PRIMARY KEY,
Col2b int NOT NULL
)
GO
CREATE VIEW MyView
AS
SELECT Col1a, Col1b, Col2a, Col2b
FROM Table1 AS t1
JOIN Table2 AS t2 ON
t2.Col2a = t1.Col1a
GO
--succeeds
UPDATE MyView
SET Col1b = 1
GO
--fails
UPDATE MyView
SET Col1b = 1, Col2b = 1
Hope this helps.
Dan Guzman
SQL Server MVP
"Ed" <Ed@.discussions.microsoft.com> wrote in message
news:864C5D55-3A5D-4F97-ABF1-9DAE7B057B33@.microsoft.com...
> Hi,
> Could someone please explain to me when the view is updatable and when it
> is not? I am under the impression that if the two tables are joined
> together
> in the view, then the view is not updatable... is it correct?
> Thanks

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