# Differences

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All datatype property classes have defined subclasses. For example, the //boundedness// class has the following subclasses: //bounded// (//bounded below, bounded above//) and //unbounded// (//unbounded below, unbounded above//). | All datatype property classes have defined subclasses. For example, the //boundedness// class has the following subclasses: //bounded// (//bounded below, bounded above//) and //unbounded// (//unbounded below, unbounded above//). | ||

+ | ==== Extended datatype ==== | ||

+ | In OntoDT, an //extended datatype// (named //'subtype'// in the ISO standard) is defined as a //IAO: data representational model// that is derived from an existing datatype by restricting the value space to a subset of the base datatype, while maintaining all operations. The base type denotes the role of a datatype as a //parametric datatype// on which a generator operates to produce a new datatype. An extended datatype is defined by a //subtype generator// that represents the relationship between the value spaces of the base type and the extended datatype. | ||

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+ | In OntoDT, we define the following classes of subtype generators: //range generator//, //selection generator//, //exclusion generator//, //size generator//, //extension generator//, and //explicit subtype generator//. Subtype generators can change the set of datatype properties valid for the base datatype, and this is the reason we do not represent them simply as subclasses of the datatype class. For example, applying the range generator to an unbound datatype will make it bounded. | ||

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+ | Using these notions, we can represent an extended datatype of any previously defined type. For example, by using a range subtype generator we can place a new upper and/or lower bound on the value space of a chosen base datatype. The //positive integer// datatype is a extended datatype of the //integer datatype// obtained by limiting the value space with a lower bound of zero. | ||

+ | |||

+ | Using these notions, we can represent an extended datatype of any previously defined type. For example, by using a range subtype generator we can place a new upper and/or lower bound on the value space of a chosen base datatype. The //positive integer// datatype is a extended datatype of the //integer datatype// obtained by limiting the value space with a lower bound of zero. | ||

===== Versions and Download ===== | ===== Versions and Download ===== | ||

==== Release version 1 ==== | ==== Release version 1 ==== |