What is a null value?

Question

Is it the same as a zore? Why are Why not? What are the three interpretations for a null values?

Answer 1

Null value means different in different places.I think this will clear your idea about null values.

Answer 2

Q: Is it the same as a zore?

A: Zore? Zorro? Zero? Not even zero nor minus one.



Q: Why are Why not?

A: If there is a time machine here, I would travel back in time and ask the person who invented the word NULL. hehe.



Q: What are the three interpretations for a null values?

A: 1. empty.. 2. nothingless... 3. nada... wait a minute?!! how the heck you know there is 3? There could be 4... or 5... or a thousand...

Answer 3

In many disciplines, the concept of null allows a three-valued logic, with null indicating "no value" or an "unknown value". The SQL database query language uses Null in this way, as do Visual Basic and its derivatives. In this model, an expression that depends on the value of a Null operand will evaluate to Null (VB) or "unknown" (SQL). So, for any A, the expressions "A = Null" and "A <> Null" are neither true nor false. However, the boolean operation "A and False" produces false, and similarly "A or True" is true, even when A is Null, because these expressions do not depend on the value of A. (Some SQL implementations may consider A = Null to be "true" if A is Null; see Null (SQL)).

Answer 4

A null is probably compiler-dependent. A null COULD be set to zero by your compiler, or it could be indeterminate - if the program does a malloc and the OS gives it a page, that page could be filled with garbage - so the proper value of null is "dont know".

Answer 5

Null in computer programming means zero, while 0 means the number 0 as represented in the computer. If you are familiar with ascii codes, then NULL has the ascii code 0, while the number 0 is stored with the ascii value of 48.



Refer to www.asciitable.com for more information

Answer 6

hi. no longer precisely. NULL means that your variable isn't particular, and that you're trying to do something with the variable you've not declared yet. you need to do following such issues as if (a!=NULL) {} to finish somewhat action with the placement the variable a is asserted and characteristic any value that you aren't any more interested in

Answer 7

null is not as a zero null is diffrent from zero.



zero also have some value that is 0



but null is nothing there is no value.

Answer 8

null is meaning of empty, (should empty)



its not like a zero. if you assinged zero means.. zero also treated as a value.

Answer 9

I suggest you look on pg 10 in the eGuide the professor placed in the docsharing =)