An attributeâÂÂvalue system is a basic knowledge representation framework comprising a table with columns designating "attributes" (also known as "properties", "predicates", "features", "dimensions", "characteristics", "fields", "headers" or "independent variables" depending on the context) and "rows" designating "objects" (also known as "entities", "instances", "exemplars", "elements", "records" or "dependent variables"). Each table cell therefore designates the value (also known as "state") of a particular attribute of a particular object.
Below is a sample attributeâÂÂvalue system. It represents 10 objects (rows) and five features (columns). In this example, the table contains only integer values. In general, an attributeâÂÂvalue system may contain any kind of data, numeric or otherwise. An attributeâÂÂvalue system is distinguished from a simple "feature list" representation in that each feature in an attributeâÂÂvalue system may possess a range of values (e.g., feature below, which has domain of {0,1,2}), rather than simply being present or absent .
AttributeâÂÂvalue systems are pervasive throughout many different literatures, and have been discussed under many different names: