From Wikipedia, the free encyclopedia
Data representation method in computing systems
Example of a
web form
with name-value pairs
A
name?value pair
, also called an
attribute?value pair
,
key?value pair
, or
field?value pair
, is a fundamental
data representation
in
computing systems
and
applications
. Designers often desire an open-ended
data structure
that allows for
future extension
without modifying existing code or data. In such situations, all or part of the
data model
may be expressed as a collection of
2-tuples
in the form
<attribute name, value>
with each element being an attribute?value pair. Depending on the particular application and the implementation chosen by programmers, attribute names may or may not be unique.
Examples of use
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Some of the applications where information is represented as name-value pairs are:
Use in computer languages
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Some
computer languages
implement name?value pairs, or more frequently collections of attribute?value pairs, as standard language features. Most of these implement the general model of an
associative array
: an unordered list of unique attributes with associated values. As a result, they are not fully general; they cannot be used, for example, to implement electronic mail headers (which are ordered and non-unique).
In some applications, a name?value pair has a value that contains a
nested
collection of attribute?value pairs. Some
data serialization
formats such as
JSON
support arbitrarily deep nesting.
[2]
Other data representations are restricted to one level of nesting, such as
INI file
's section/name/value.
See also
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References
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