Comment on PR01 Schemas: oBIX Schemas and backward incompatibilty

We seem to have radically redefined the effects of the schema for oBIX in that we have radically simplified the required fields. This may be good or bad: I merely assert that it is.

For this letter I used ALTOVA XML Spy, latest version. Notice that for all URI.s, this tool always generates a link to the company…

If I generate a legal OP from the oBIX 1.0 Schema, I generate the following artifact:

<?xml version="1.0" encoding="UTF-8"?>

</list>

</real>

</abstime>

</str>

</bool>

</int>

</uri>

</reltime>

</enum>

</obj>

</op>

If I use the new Schemas, those in the current public review, I generate the following:

<?xml version="1.0" encoding="UTF-8"?>

<obix:op in="String" out="String" name="String" href="String" is="String" null="true" displayName="String" display="String" icon="http://www.altova.com" precision="0" status="ok" unit="String" writable="true" xsi:schemaLocation="http://obix.org/ns/schema/1.1 obix-v1.1-wd13.xsd" xmlns:obix="http://obix.org/ns/schema/1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>

This is quite different. In part this is because the current schema often uses strings rather than URIS. 1.0, though, has almost no subtyping, or referencing, each of which desirable for tooling. If I go back to 1.0, and make the following changes:

1) Use NIEM rules for naming types and references, i.e. foo is of type FooType. Current schema uses the pattern foo is of type Foo which is confusing

2) Define all attribute types before use

<xs:attribute name="display" type="DisplayType"/>

<xs:simpleType name="DisplayType">

<xs:restriction base="xs:string" />

</xs:simpleType>

<xs:attribute name="displayName" type="DisplayNameType"/>

<xs:simpleType name="DisplayNameType">

<xs:restriction base="xs:string" />

</xs:simpleType>

<xs:attribute name="href" type="HrefType"/>

<xs:simpleType name="HrefType">

<xs:restriction base="xs:anyURI" />

</xs:simpleType>

<xs:attribute name="icon" type="IconType"/>

<xs:simpleType name="IconType">

<xs:restriction base="xs:anyURI" />

</xs:simpleType>

<xs:attribute name="name" type="NameType"/>

<xs:simpleType name="NameType">

<xs:restriction base="xs:NMTOKEN" />

</xs:simpleType>

<xs:attribute name="null" type="NullType"/>

<xs:simpleType name="NullType">

<xs:restriction base="xs:boolean" />

</xs:simpleType>

<xs:attribute name="writable" type="WritableType" default="false"/>

<xs:simpleType name="WritableType">

<xs:restriction base="xs:boolean"/>

</xs:simpleType>

3) Contract Type is currently defined as a collection of anyURIs. Is is really a collection of oBIX HREFs?

4) Global element err redefines Err[Type] rather than using type Err[Type]

5) Add Unit (anyURI) to list of Global Attributes

6) As currently defined, err is an instance of type Err which is identical to the Obj type. The object ref is an instance of ObjectType. Suggest making usage consistent between two types, I,e., Make each an instance of type obj or, preferred, make a type for each

7) Make precision a global attribute

I get a schema that was used to generate the following artifact:

<?xml version="1.0" encoding="UTF-8"?>

</feed>

</list>

</real>

</abstime>

</str>

</bool>

</int>

</uri>

</reltime>

</enum>

</obj>

</op>

So I tried to normalize the PR01 schemas, using the same comments as for 1.0:

Some issues:

1) Obix:REAL is missing Max and Min

2) “of” and “in” are strings rather than contracts

3) In 1/0. “bool” has a range. In PR01, it does not. I think 1.1 PR01 is correct.

4) AbsTime “val” should be "xs:dateTime"

5) RelTime val, min, max should all be of type duration (missing Val)

6) Add “Type” to all types

This now generates sample XML as follows

<?xml version="1.0" encoding="UTF-8"?>

<obix:op in="String" out="String" obix:name="NMTOKEN" obix:href="http://www.altova.com" obix:is="http://www.altova.com" obix:null="true" obix:displayName="String" obix:display="String" obix:icon="http://www.altova.com" obix:precision="0" obix:status="ok" obix:unit="http://www.altova.com" obix:writable="false" xsi:schemaLocation="http://docs.oasis-open.org/obix/ns/2013 obix-v1.1-pr01%20TC.xsd" xmlns:obix="http://docs.oasis-open.org/obix/ns/2013" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>

Which maintains the new look, but is better typed (see URIs)

Sample Schemas and examples can be found at:

https://www.oasis-open.org/apps/org/workgroup/obix/download.php/50223/Notes%20to%20options%20on%20Schemas.docx

"Energy and persistence conquer all things." -- Benjamin Franklin

Toby Considine
TC9, Inc

OASIS TC Chair: oBIX & WS-Calendar

OASIS TC Editor: EMIX, Energy Interoperation

SGIP Smart Grid Architecture Committee

Email: Toby.Considine@gmail.com
Phone: (919)619-2104

http://www.tcnine.com
blog: http://www.NewDaedalus.com

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