On Jun 12, 2005, at 10:12 PM, Dan Kennedy wrote:
If I do have UNIQUE in a col declaration, will creating another index
on that column slow things down? Before I knew what you write above, I
had gone ahead and create a UNIQUE INDEX on col b. I am not sure if
that was slowing the operations, so I just want to confirm that.
Slows down writes and makes the database larger.
Second, it seems logical that if I have UNIQUE then I don't have to
declare NOT NULL. For example,
Not redundant. UNIQUE does not imply NOT NULL.
thanks for all the valuable clarification. However, the above seems
contradictory. After all, if more than one row can be NULL, then they
won't be UNIQUE! what gives?
--
Puneet Kishor
