At 09:36 AM 10/18/2012, Stephen Markson wrote:
Quick story illustrating why you should never use DATETIME for a
unique identifier:
We hired an experienced, reputable firm to create a web commerce app
for us. They
used a 12-digit order number. We asked them to reduce it to 9 digits
so we could use
(R:Base) integers in our application. At that time, I noticed that
the order number
was incrementing proportionally to the time, at a rate of 1 per 60
microseconds. I
pointed out that decreasing the order # to 9 digits would increase
the probability
of a duplicate order # by a factor of 1,000. They said they'd get
back to me. A few
weeks later we got two orders with identical order numbers. To say
the least, I was
surprised that they had no primary key based on order #!
Stephen,
Very interesting story ...
Did you know that R:BASE eXtreme 9.5 (64) include BIGNUM and GUID
data types to
handle such circumstances?
In addition to so many cool features/enhancements, Globally Unique
Identifier (GUID)
data type in R:BASE eXtreme 9.5 (64) can also be used for a unique
Row Identifier.
For complete details ...
http://www.rbase.com/rbg95
http://www.rbase.com/rbg95/compare.php
Very Best R:egards,
Razzak.
www.rbase.com
www.facebook.com/rbase
