Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 10: Views
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from the first index as a reference point. That said, nothing comes for free — there are some restrictions
about when you can and can’t build indexes on views (I hope you’re ready for this one — it’s an awfully
long list!):
❑ The view must use the SCHEMABINDING option.
❑ If it references any user-defined functions (more on these later), then these must also be schema
bound.
❑ The view must not reference any other views — just tables and UDFs.
❑ All tables and UDFs referenced in the view must utilize a two-part (not even three-part and
four-part names are allowed) naming convention (for example dbo.Customers, BillyBob
.SomeUDF) and must also have the same owner as the view.
❑ The view must be in the same database as all objects referenced by the view.
❑ The ANSI_NULLS and QUOTED_IDENTIFIER options must have been turned on (using the SET
command) at the time the view and all underlying tables were created.
❑ Any functions referenced by the view must be deterministic.
To create an example indexed view, let’s start by making a few alterations to the CustomerOrders_vw
object that we created earlier in the chapter:
ALTER VIEW CustomerOrders_vw
WITH SCHEMABINDING
AS
SELECT sc.AccountNumber,
soh.SalesOrderID,
soh.OrderDate,
sod.ProductID,
pp.Name,
sod.OrderQty,
sod.UnitPrice,
sod.UnitPriceDiscount * sod.UnitPrice * sod.OrderQty AS TotalDiscount,
sod.LineTotal
FROM Sales.Customer AS sc
INNER JOIN Sales.SalesOrderHeader AS soh
ON sc.CustomerID = soh.CustomerID
INNER JOIN Sales.SalesOrderDetail AS sod
ON soh.SalesOrderID = sod.SalesOrderID
INNER JOIN Production.Product AS pp
ON sod.ProductID = pp.ProductID;
The big thing to notice here is that we had to make our view use the SCHEMABINDING option. This is
really just the beginning though — we don’t have an indexed view as yet. Instead, what we have is a
view that can be indexed. Before we actually build the index, let’s get a baseline of how queries against
our view would currently be executed. Take a simple SELECT against the view:
SELECT * FROM CustomerOrders_vw;
Seems simple enough, but remember that there are four tables underlying this view. If we choose to display
the estimated execution plan (one of the icons on the toolbar) as shown in Figure 10-5, we see a
somewhat complex set of steps to execute our query.