null (redirected from null cell)

null

A character that is all 0 bits. Also written as "NUL," it is the first character in the ASCII and EBCDIC data codes. In hex, it displays and prints as 00; in decimal, it may appear as a single zero in a chart of codes, but displays and prints as a blank space.

Nulls are naturally found in binary numbers when a byte contains all zeros, and they are used to pad fields (see padding). A null may function as a delimiter; for example, in C, a null character is inserted at the end of a character string to mark the end of the text.

The Null Is the First

Note the first character at the top of this chart of ASCII characters. The 00 means 0000-0000 bits.

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null

1. Maths

a. quantitatively zero

b. relating to zero

c. (of a set) having no members

d. (of a sequence) having zero as a limit

2. Physics involving measurement in which an instrument has a zero reading, as with a Wheatstone bridge

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(programming)

null - A special value used in several languages to represent the thing referred to by an uninitialised pointer. A special value that may be stored in some database columns to represent an unknown, missing, not applicable, or undefined value. Nulls are treated completely differently from ordinary values when evaluating SQL expressions and there are several SQL constructs for dealing with nulls.