Seagate ST43401N/ND Technické informace stáhnout pdf (Strana 79)

Migrating to Sybase Adaptive Server Enterprise 11.5 5-25

Adaptive Server Enterprise 11.5 If Your Current Version is 4.x, 10.x, or 11.0.x

query such as the example, the query process must scan all index

pages where age = 30 to ﬁnd the ﬁrst qualifying row that is larger:

Don't:

select EmployeeName

from Employee

where age > 30

However, when the same query is written in either of two ways,

the query process goes directly to the ﬁrst qualiﬁed row and

starts processing from there:

Do:

select EmployeeName

from Employee

where age >= 30 + 1

Or do:

select EmployeeName

from Employee

where age >= 31

Learn More About Coding For Performance

To learn more about programming for performance, as well as

monitoring and tuning your system, consider taking Sybase’s

“Migrating to Adaptive Server 11.5” course. For more information,

see Chapter 1, “Introduction and Guide to Resources”.

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Seagate ST43401N/ND Technické informace Strana 79