By default, when you define a primary key in the create table statement, it uses a clustered index. However, a clustered key is best used to support queries that return more than one row. For example, if you have a date field that is often used to return activity for a range of days, a clustered index will be much faster than a nonclustered one. To preserve your clustered index for other columns, you can add the keyword nonclustered to the primary constraint definition; that is, constraint pkaccount primary key nonclustered (acctid).