Oracle Concept

[dba_admin]

In terms of resource usage (rollback segment and other resource), what type of transaction uses more "rollback segment" than the other transaction?

a. Update
b. Delete
c. Insert

And, why?

[jmodic]

In terms of rollback space ussage, INSERT requires less than UPDATE, UPDATE (generally) requires less than DELETE. Why? Ask yourself what information does the database need to be able to rollback the changes. For INSERT, all it needs to know is the ROWID of the inserted row. For UPDATE, it needs the ROWID and the values of the *changed* column before the change. For DELETE it needs ROWID and values of *all* the columns befor the DELETE.