Re: [xml-dev] Need a language whiz: An XML Schema "specifies" howdata is

[bryan rasmussen <rasmussen.bryan@gmail.com>]

Theoretically, although I have never seen it with XSD and would
probably think it was a weird use of the language, you could have
multiple schemas for validating documents in the same namespace.
This is implied by some of the other emails in this thread, where one
has a chain of validations, and each validation step in the chain
narrowed the range of possible validation errors for the next step.

Remembering Joe English's plea for sanity in the use of namespaces
http://www.flightlab.com/~joe/sgml/sanity.txt I would say that this
kind of validation chain if implemented using XSD for multiple
validation steps might be defined as the full-blown OCD validation
pattern.

However it is totally a reasonable way of validating documents with a
schematron solution, to route the documents into the right department
for handling documents that are overall valid, but need some extra
checking. When done using schematron it is the slightly anal
validation pattern.

Cheers,
Bryan Rasmussen

On Wed, Jan 3, 2018 at 5:24 PM, Michael Kay <mike@saxonica.com> wrote:
> The essence of the semantics of XSD is that the specification defines a process, variously called "validation" or "assessment", that takes a schema and an instance document as input and produces an assessment outcome as its result.
>
> assess(schema, instance) => outcome
>
> (It's slightly more complicated than that because you can specify other inputs to the assessment, e.g. strict/lax).
>
> The specification does not use any specific term (such as "describes" or "constrains") for the relationship between a schema and the set of instance documents for which assessment has an outcome labeled "valid". You're perfectly welcome to use a term such as "describes" for this relationship if you wish, but it's not a term-of-art in XSD itself; so if you use it, you should say carefully what you mean by it.
>
> Michael Kay
> Saxonica
>
>
>> On 3 Jan 2018, at 14:40, bryan rasmussen <rasmussen.bryan@gmail.com> wrote:
>>
>> The word choices betray viewpoints of reality -
>> stating or specifying how data is to be structured assumes a blank
>> canvas and the schema tells you how that canvas may be filled
>> constrains assumes that data is a realm of many, perhaps infinite
>> possibilities, XML Schema then constrains or limits the possible to
>> the manageable.
>>
>> I am a specifying how data is to be structured man myself.
>>
>> On Mon, Nov 13, 2017 at 2:13 PM, Costello, Roger L. <costello@mitre.org> wrote:
>>> Hi Folks,
>>>
>>>
>>>
>>> Which of the following is most accurate and why?
>>>
>>>
>>>
>>> An XML Schema specifies how data is to be structured.
>>> An XML Schema describes how data is to be structured.
>>> An XML Schema states how data is to be structured.
>>> An XML Schema constrains the structure of data.
>>> An XML Schema structures data.
>>> An XML Schema describes data.
>>> An XML Schema constrains data.
>>> Other (what?)
>>>
>>>
>>>
>>> /Roger
>>>
>>>
>>
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>