DUAL behavior change
While reading the book Expert Oracle Database Architecture, I noticed a very important bit of information about the DUAL table. In 10g, Oracle does not do a full table scan on DUAL if it does not need to. This is not the case in versions prior to 10g. To illustrate: (more…)
Filed in Oracle, Tips with 5 Comments | Tags: 10g, dualInsert into DUAL
On the Oracle-l mailing list, Jared Still posted a message about a little experiment he did which concluded that Oracle (10gR1) always makes sure that DUAL returns one and only one row even if it contains more than one row.
I have repeated the experiment on my Oracle 10g XE database (Important: Do not do this dangerous stuff on your production database. Never insert/delete/update DUAL): (more…)
Filed in Oracle with 9 Comments | Tags: 10g, dual
