Information Technology Reference
In-Depth Information
In addition to these standard attributes a user can define his/her own extra
attributes. Each new attribute has a number of descriptors. The obligation column
indicates whether a descriptor is mandatory (M), conditional (C), optional (O) or
defaulted (D).
Descriptor of attribute
Obligation
ATTRIBUTE_NAME
M
ATTRIBUTE_DEFINITION
M
ATTRIBUTE_OBLIGATION
M
ATTRIBUTE_CONDITION
C
ATTRIBUTE_MAXIMUM_OCCURRENCE
M
ATTRIBUTE_VALUE_TYPE
M
ATTRIBUTE_MAXIMUM_SIZE
O
ATTRIBUTE_ENUMERATION_VALUES
C
ATTRIBUTE_COMMENT
O
ATTRIBUTE_INHERITANCE
D
ATTRIBUTE_DEFAULT_VALUE
C
ATTRIBUTE_VALUE_EXAMPLE
O
ATTRIBUTE_SCOPE
D
The standard defines, for each of the standard attributes, all the above descriptors.
Particular encodings are defined, the one of most interest being perhaps the XML
encoding [
62
].
Related, broader, capabilities are provided by the multi-part standard ISO/IEC
11179 [
63
] which is under development to represent this kind of information in a
“metadata” registry.
7.5.1.1 Complex Semantics
In simple semantics we have the ability to provide limited meaning about a
data entity, with some very limited relationship information. For example the
RELATIONSHIP attribute of DEDSL is defined as “used to express a relationship
between two entity definitions when this relation cannot be expressed using a pre-
cise standard relational attribute. In that case the relationship is user-defined and
expressed using free text”. More formal specifications of relationships, and more
complex relationships, are provided in tools such as those based RDF and OWL.
Chapter 8
provides further information about these aspects.
7.6 Other Representation Information
“Other” Representation Information is a catch-all term for Representation
Information which cannot be classified as Structure or Semantics. The follow-
ing sub-sections discuss a number of possible types of “Other” Representation
Information.
