Null (computing)
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Revision as of 17:52, 22 September 2016 by Karl Jones (Talk | contribs) (Created page with "In computing, '''null''' has different definitions in different contexts. The general idea is "nonexistence". == Definition == * Null (SQL), a special marker and ...")
In computing, null has different definitions in different contexts.
The general idea is "nonexistence".
Definition
- Null (SQL), a special marker and keyword in SQL indicating that something has no value.
- Null character, the zero-valued ASCII character, also designated by NUL, often used as a terminator, separator or filler. This symbol has no visual representation.
- Null device, a special computer file that discards all data written to it
- Null modem, a specially wired serial communications cable
- Null Object pattern, a software design pattern using an object with defined neutral behavior
- Null pointer (sometimes written NULL, nil, or None), used in computer programming for an uninitialized, undefined, empty, or meaningless value
- Null string, the unique string of length zero (in computer science and formal language theory)
- Null-terminated string, a character string of which the length is determined by the first null-character (in programming language C and related languages)
- Nullable type, a feature of some statically-typed programming languages which allows a data type to be set to the special value NULL
