Wednesday, April 8, 2009

All about Dual Table : AskTom

A very very interesting article from AskTom on dual table, its purpose and usage and everything else about it...

Here's some excerpts from it, leaving the rest for reading...
"DUAL is owned by SYS.  SYS owns the data dictionary, 
therefore DUAL is part of the data dictionary. You are not to modify the data dictionary
via SQL ever -- wierd things can and will happen"


the optimizer understands dual is a magic, special 1 row table.  It stopped on the 
select * because there is to be one row in there. Its just the way it works.
Read the rest of article here...

Ask Tom "All about the DUAL table "
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