Q * 2. Describe "optimistic searching"? What does TRUNCATE do? 1

[geriatric]

Can't respond to questions relating to the "TRUNCATE as opposed to DELETE".

Also, don't understand the "optimistic search" concept.

(Now can I type "Help"!) Thanks. Geriatric
[sig][/sig]

 

[carp]

TRUNCATE (by default) releases all extents that have been added to the segment since the segment was created. Also, the High Water Mark (HWM) is reset to the beginning of the segment. The rows of data are thus not deleted; however, since they are beyond the HWM, they are not accessible. Since this is all DDL, no rollback and a minimum amount of redo information is written.
DELETE, on the other hand, is DML. Consequently, it does generate rollback and a higher amount of redo information. So, while it CAN be rolled back, it also consumes considerably more in the way of resources.

Not sure about "Optimistic Searching". [sig][/sig]

 

[geriatric]

Got it! Thanks very much. geriatric [sig][/sig]

 

[bigscouse]

Remember TRUNCATE efectivley removes all the data in the table, it is non selective.
DELTE only removes what results from the WHERE clause. [sig]<p>Ged Jones<br><a href=mailto:gedejones@hotmail.com>gedejones@hotmail.com</a><br><a href= > </a><br>Top man[/sig]