Drew Wutka
DWUTKA at Marlow.com
Mon Mar 30 12:03:49 CDT 2009
Ah, but if I were to ask you the temperature of something that was 0 Kelvin, would you not answer '0 Kelvin'? Temperature is the average molecule kinetic energy of a substance. 0 K, or absolute 0, is the absence of all molecule kinetic energy. Yet 0 K is a valid measurement. Just as Null is a value for a field that has no value! Drew (this is the way to start off a Monday!) <vbg> -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Charlotte Foust Sent: Monday, March 30, 2009 10:33 AM To: Access Developers discussion and problem solving Subject: Re: [AccessD] An Interesting question No, Drew, Null is NOT a representation of a value, it is a representation of the absence of a value. A hole in the ground exists and has a shape. A null has no shape because it doesn't exist! Charlotte Foust -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Drew Wutka Sent: Sunday, March 29, 2009 7:00 PM To: Access Developers discussion and problem solving Subject: Re: [AccessD] An Interesting question LOL. Sure, I love a good debate...it's been to quiet around here anyways! You're arguments are based on pure logic, which don't always hold true when it comes to a computer system. Ironic, eh? Case in point, it is logical to assume that 0=0, but in some instances, 0<>0. It can happen when you use a signed integer, you can end up with -0. In that case, even though the numeric value is 0. the sign bit is turned on, so a computer will see 0<>-0. Mathematically, there is no such thing as a -0, but a computer can run into such an occurrence. Now, null is a value representation just as 5, or 'hello', or 2/10/1999 is a value representation. 5 means nothing other then 5. In a field of 'NumberOfUnits', then 5 represents the number of units. Null is a field value that represents a 'null value', which is a value that has not been set. It's a special condition. An empty string is not null, it's an empty string. Null represents a value that has never been set before (because as far as I know, you can't actually set a field to null once it has had a value set...). You're ball... ;) Drew -- AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com The information contained in this transmission is intended only for the person or entity to which it is addressed and may contain II-VI Proprietary and/or II-VI Business Sensitive material. If you are not the intended recipient, please contact the sender immediately and destroy the material in its entirety, whether electronic or hard copy. You are notified that any review, retransmission, copying, disclosure, dissemination, or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited.