Unable to perform delete on View SQL Server 2005

问题:

I am unable to perform a delete on a View. Everything worked fine on the individual tables.

EDIT1: Added Trigger

CREATE TRIGGER myTrigger
ON [ViewName]
INSTEAD OF DELETE
AS
DELETE
FROM [ViewName]
WHERE [ColumnName] < DATEADD(Day, -90, GETDATE())

I got the following error before adding a trigger

View or Function "blah" is not updateable because the modification affects multiple base tables>

回答1:

Okay, let's imagine one instance where this error will occur (since you haven't shown your view definition).

Let's assume we have a view:

CREATE VIEW dbo.V1
with schemabinding
as
    select 'T1' as TabName,T1ID as ID,ImportantDate from dbo.T1
    union all
    select 'T2',T2ID,ImportantDate from dbo.T2

is we now attempt:

DELETE from dbo.V1 where ImportantDate < DATEADD(day,-90,CURRENT_TIMESTAMP)

we'll get the error you've shown (or similar). So what we need is a trigger:

CREATE TRIGGER T_V1_D
on dbo.V1
instead of delete
as
    set nocount on
    delete from dbo.T1 where T1ID in (select ID from deleted where TabName = 'T1')
    delete from dbo.T2 where T2ID in (select ID from deleted where TabName = 'T2')

This trigger gets considerably more complex to write if there's no easy way to correlate rows from the deleted psuedo-table with which rows need to be deleted from each base table.

回答2:

DELETE command: http://msdn.microsoft.com/en-us/library/ms189835.aspx

The view referenced by table_or_view_name must be updatable and reference exactly one base table in the FROM clause of the view. For more information about updatable views, see CREATE VIEW (Transact-SQL).

CREATE VIEW command, Updatable Views: http://msdn.microsoft.com/en-us/library/ms187956.aspx

Any modifications, including UPDATE, INSERT, and DELETE statements, must reference columns from only one base table.

回答3:

Are you referencing columns from multiple tables? If so that error sounds pretty straight forward.

You can however, use a stored procedure instead of a view to execute this.