Ontology: Fundamentals and Languages ◾ 41
Global declarations state the elements in documents that instantiate the schema:
<xsd:element name = “tag1” type = “Tag1Type”/>
<xsd:element name = “tag2” type = “Tag2Type”/>
<xsd:element name = “tag3” type = “Tag3Type”/>
An element declaration usually species the name and type of element, for example
a built-in:
xsd:string ::= <char>+
xsd:boolean ::= false | true
xsd:decimal ::= (+ | -)?<digit>+(.<digit>*)?
xsd:double ::= IEEE double precision float
xsd:float ::= IEEE single precision float
xsd:integer ::= (+|-)?<digit>+
xsd:duration ::= P<int>Y<int>M<int>DT<int>H<int>M<int>S
xsd:time ::= <hours>:<mins>:<secs>
<hours>, <mins> ::= <int>, <secs> ::= <decimal>
xsd:date ::= <CCYY>-<MM>-<DD>
xsd:anyURI ::= <URI>
xsd:ID ...