[
Lists Home |
Date Index |
Thread Index
]
Hi.
> Suppose that:
>
> 1. There exist a collection of "components", and each component is
> well-defined and understood.
>
> 2. There does NOT exist any rules which specify how the components
> should be
> assembled.
Either no relation exists between the information (and I don't think this
is what you mean) or there are some rules relating the pieces of
information and it boils down to questions about how to represent and
communicate the relationships:
- the document structure could imply information about the relationships
of the
information
- a supplemental structured document could hold information about
relationships
(meta data)
- your systems and my systems could both implement the same sets of rules
about
relationships
In all three cases but especially in the third, some out-of-band
communication is often needed to establish a working relationship where we
agree on the meaning of components and their relationships.
> Can information be transmitted in a world where the building blocks are
> understood, but no grammar exists?
I'm not sure that I see a case where building blocks exist without a
grammar. You always need rules to assemble the blocks, then rules to
assemble the assemblies. The smaller you break the blocks up, the simpler
the rules get, but you still need to express something about the
information. You can mark it up or use a schema or tell me what it is over
the phone or whatever.
> Is a grammar necessary for information transfer?
You certainly don't have to explicitly model every relationship that your
recipient may be interested in. That's what queries (transforms) are
often used for.
> Consider XML Schemas. Suppose that:
>
> 1. An XML Schema declares a bunch of independent elements (i.e.,
> components)
> and each component is understood. For example, here's a Book component:
>
> <xsd:element name="Book">
> <xsd:complexType>
> <xsd:all>
> <xsd:element name="Title" type="xsd:string"/>
> <xsd:element name="Author" type="xsd:string"/>
> <xsd:element name="Date" type="xsd:date"/>
> <xsd:element name="ISBN" type="xsd:string"/>
> <xsd:element name="Publisher" type="xsd:string"/>
> </xsd:all>
> </xsd:complexType>
> </xsd:element>
>
> Here's a BookCover component:
>
> <xsd:element name="BookCover">
> <xsd:complexType>
> <xsd:choice>
> <xsd:element
> name="Hardcover"><xsd:complexType/></xsd:element>
> <xsd:element
> name="Softcover"><xsd:complexType/></xsd:element>
> </xsd:choice>
> </xsd:complexType>
> </xsd:element>
>
> Everyone understands the meaning of each component in the Schema.
>
> 2. But there is no declaration tying the components together, e.g.,
> there is
> no overarching element declaration that relates the Book component with
> the
> BookCover component.
>
> If I create an XML instance document using the components and send the
> instance document to you, will you be able to understand my data?
If you are saying that the only way to have an agreement about this is to
code it into the XSD then I'm not sure I agree. I do think you have
demonstrated that it's possible to model books and cover types in a way
that makes it unnaturally difficult to relate the two.
-------->Nathan
>
> /Roger
>
>
>
>
> -----------------------------------------------------------------
> The xml-dev list is sponsored by XML.org <http://www.xml.org>, an
> initiative of OASIS <http://www.oasis-open.org>
>
> The list archives are at http://lists.xml.org/archives/xml-dev/
>
> To subscribe or unsubscribe from this list use the subscription
> manager: <http://www.oasis-open.org/mlmanage/index.php>
>
--
.:||:._.:||:._.:||:._.:||:._.:||:._.:||:._.:||:._.:||:._.:||:._.:||:._.:||:.
Nathan Young
A: ncy1717
E: natyoung@cisco.com
|
