I want to create the following indexed view:
CREATE VIEW [Cic].[vwMarker] WITH SCHEMABINDING
AS
Select
SubId,
marker.EquipmentID,
marker.ReadTime,
marker.CdsLotOpside,
marker.CdsLotBackside,
marker.CdteLotOpside,
marker.CdTeLotBackside
From dbo.Marker
Where dbo.Marker.ReadTime >= Convert(dateTime,'10/5/2011',120)
GO
CREATE UNIQUE CLUSTERED INDEX IX_vwMarker_ReadTime_EquipmentID
ON Cic.vwMarker (ReadTime, EquipmentID);
This works fine. However, what I would really like to do is to only include rows in this view that are two days old or newer, as of the current date/time the view is queried. I can't find a way to do this because I cannot use GetDate() in the Where predicate because it is non-deterministic. In other words, I'd like to do something like this, but cannot:
Where dbo.Marker.ReadTime >= Convert(dateTime,DateAdd(dd,-2,GetDate()) ,120)
Is there a way around this?
AFAIK you aren't going to get around the deterministic function for the SCHEMABINDING requirement. You'll always receive the error
The function 'getdate' yields nondeterministic results. Use a deterministic system function, or modify the user-defined function to return deterministic results.
If Marker is just a single table, I'm not sure that an indexed view would have any performance benefit over a normal view against the table with the same clustered index on the underlying table of (ReadTime, EquipmentID)
However, if "Marker" is itself a composite such as a VIEW
, OR if you don't want to change the Clustered Index on the Marker table, then you might consider something like:
- Create a schema bound view without the ReadDate filter (vwMarker)
- Create the Indexed View on the unfiltered view
- Create a second, non schema-bound view vwMarkerRecent or such, which adds in the non-deterministic
GetDate
filter.
Sql Fiddle example here
i.e. Something like:
CREATE VIEW [Cic].[vwMarker] WITH SCHEMABINDING
AS
Select
SubId,
marker.EquipmentID,
marker.ReadTime,
marker.CdsLotOpside,
marker.CdsLotBackside,
marker.CdteLotOpside,
marker.CdTeLotBackside
From dbo.Marker
-- Add only Deterministic where filters here
GO
CREATE UNIQUE CLUSTERED INDEX IX_vwMarker ON Cic.vwMarker (ReadTime, EquipmentID)
GO
CREATE VIEW [Cic].[vwRecentMarker] -- Not Schema Bound
AS
Select
vm.SubId,
vm.EquipmentID,
vm.ReadTime,
vm.CdsLotOpside,
vm.CdsLotBackside,
vm.CdteLotOpside,
vm.CdTeLotBackside
From cic.vwMarker vm
Where vm.ReadTime >= Convert(dateTime,DateAdd(dd,-2,GetDate()) ,120)
GO