The Nature of NULL - Page 2

In final reply to this inquiry I must observe that NULL is not equal to anything. Any conditional statement where NULL is compared to something will be false. Where "" represents an empty string, if one writes the statement, ["" == ""], or in English, "if an empty string is equal to an empty string," it evaluates as a true statement. However if one writes the statement [NULL == NULL], or in English, "if NULL is equal to NULL," it evaluates to a false statement. Since an empty string is equal to another empty string, but NULL is not equal to NULL, then NULL cannot be the same thing as an empty string.

Why NULL is Important

Just as early civilizations had no concept of zero, early discourses of NULL struggle with it. Where we can argue if you have zero apples, is the same as having nothing. Yet it can be the absence of something that is known. Zero can be having none of something. But NULL is not even knowing what the something is that you don't have.

An apple basket can contain zero apples as a way to say, "Hey, this basket is for apples!" So is zero greater than NULL. Because with null we don't know what the basket is for. We may not even have a basket at all.

There are a great number of operations that we couldn't do well or efficiently if we didn't have NULL. So understanding what we are asking when we look for NULL is important. Whenever we have a search for things that don't match something else, we are searching for NULL, even if the values themselves are not NULL. We do this a lot, and we couldn't do it without NULL.

Article Author: Roy Hayward

Roy studied chemistry and political science in college, and spent his early days in computers playing with them as a hobby, but discovered that they made a better career. Entering into the field as end user tech support, Roy move on to system and …

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