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

The CREATE INDEX Statement
The CREATE INDEX statement does exactly what it sounds like — it creates an index on the specified
table or view based on the stated columns.
The syntax to create an index is somewhat drawn out and introduces several items that we haven’t
really talked about up to this point:
CREATE [UNIQUE] [CLUSTERED|NONCLUSTERED]
INDEX ON ( [ASC|DESC] [,...n])
INCLUDE ( [, ...n])
[WITH
[PAD_INDEX = { ON | OFF }]
[[,] FILLFACTOR = ]
[[,] IGNORE_DUP_KEY = { ON | OFF }]
[[,] DROP_EXISTING = { ON | OFF }]
[[,] STATISTICS_NORECOMPUTE = { ON | OFF }]
[[,] SORT_IN_TEMPDB = { ON | OFF }]
[[,] ONLINE = { ON | OFF }
[[,] ALLOW_ROW_LOCKS = { ON | OFF }
[[,] ALLOW_PAGE_LOCKS = { ON | OFF }
[[,] MAXDOP =
]
[ON { | | DEFAULT }]
There is legacy syntax available for many of these options, and so you may see that syntax put into use
to support prior versions of SQL Server. That syntax is, however, considered deprecated and will be
removed at some point. I highly recommend that you stay with the newer syntax where possible.
Loosely speaking, this statement follows the same CREATE syntax
that we’ve seen plenty of already (and will see even more of). The primary hitch in things is that we
have a few intervening parameters that we haven’t seen elsewhere.
Just as we’ll see with views in our next chapter, we do have to add an extra clause onto our CREATE
statement to deal with the fact that an index isn’t really a stand-alone kind of object. It has to go together
with a table or view, and we need to state the table that our column(s) are ON.
After the ON () clause, everything is optional. You can mix
and match these options. Many of them are seldom used, but some (such as FILLFACTOR) can have a
significant impact on system performance and behavior, so let’s look at them one by one.
ASC/DESC
Chapter 9: SQL Server Storage and Index Structures
There is a similar but sufficiently different syntax for creating XML indexes. That
will be handled separately at the end of this section.
These two allow you to choose between an ascending and a descending sort order for your index. The
default is ASC, which is, as you might guess, ascending order.
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