Proposal for datatypes at 3F2F

Hello,

This is the proposal for the datatype system of OWL 2 worked out at 3F2F.

Regards,

	Boris



1. Numeric Datatypes
----------------------

Datatype:    owl:realPlus
Value space: The set of all real numbers plus NaN, +inf, -inf, and -0.
Facets:      minInclusive, minExclusive, maxInclusive, and maxExclusive
Constants:   None
Note 1:      The value +0 is already available in the set of all real numbers.
Note 2:      This is the base datatype for all other numeric datatypes.
Note 3:      The facets are inherited by all numeric datatypes and I don't list them separately.

Datatype:    owl:real
Value space: The set of all real numbers (without NaN, +inf, -inf, and -0).
Constants:   None
Note:        The value space is a subset of owl:realPlus.

Datatype:    xsd:integer
Value space: The set of all integers. The value space is the subset of owl:number.
Constants:   The same as in XML Schema. The normative requirement would be to support all two's complement 64 bit integers.
Note:        We would also support all the derivatives of xsd:integer, which I won't list separately.

Datatype:    xsd:float and xsd:double
Value space: The discrete set of all floats (resp. doubles) representable using the XML Schema spec (including NaN, +inf, -inf, and
-0).
Constants:   The same as in XML Schema.
Note:        Thus, the value space is a finite subset of owl:realPlus, but not of owl:number (because of the special values).

Datatype:    xsd:decimal
Value space: The subset of owl:real containing all decimal numbers.
Constants:   The same as in XML Schema. The normative requirement for implementations would be to support constants as in XML Schema
(which is, I think, all constants with 18 digits).

2. Additional datatypes
-------------------------

The value space would be disjoint from all other datatypes.

Datatype:    xsd:boolean
Value space: The set { true, false }.
Facets:      none

Datatype:    xsd:hexBinary
Value space: The set of all finite string of octets (= bytes).
Facets:      length, minLength, maxLength

Datatype:    xsd:base64Binary
Value space: Exactly the same set as in the case of xsd:hexBinary
Facets:      length, minLength, maxLength
Note:        This datatype exists only to allow for BASE64-encoded constants.

3. Time and date
------------------

Datatype:    xsd:dateTime
Value space: The time line as in the XML Schema 1.1. It is domain-zone independent; that is, it represents the global (i.e.,
"universe") time.
Constants:   Only constants containing the time zone are allowed. Applications may repair missing time zones in some nonstandard
way.
Facets:      minInclusive, minExclusive, maxInclusive, and maxExclusive
Note:        We deferred the issue whether this is going to be called owl:dateTime instead of xsd:dateTime.

4. String datatypes
---------------------

Deferred to a separate subgroup.

Received on Tuesday, 29 July 2008 14:25:08 UTC