Hi Markus,
No. I was just thinking in adding something like Location Paths (http://www.w3.org/TR/xpath#location-paths) or we could make use of what the OGC defines in WFS:
From WFS specifications (1.0.0 and 1.1.0)
""" This specification does not require a WFS implementation to support the full XPath language. In order to keep the implementation entry cost as low as possible, this specification mandates that a WFS implementation must support the following subset of the XPath language: 1. A WFS implementation must support abbreviated relative location paths. 2. Relative location paths are composed of one or more steps separated by the path separator '/'. 3. The first step of a relative location path may correspond to the root element of the feature property being referenced or to the root element of the feature type with the next step corresponding to the root element of the feature property being referenced. 4. Each subsequent step in the path must be composed of the abbreviated form of the child:: axis specifier and the name of the feature property encoded as the principal node type of element. The abbreviated form of the child:: axis specifier is to simply omit the specifier from the location step. 5. Each step in the path may optionally contain a predicate composed of the predicate delimiters '[' and ']' and a number indicating which child of the context node is to be selected. This allows feature properties that may be repeated to be specifically referenced. 6. The final step in a path may optionally be composed of the abbreviated form of the attribute:: axis specifier, '@', and the name of a feature property encoded as the principal node type of attribute. """ In the WFS schema there is a type called XlinkPropertyName to care of this, but I don't know if this is suitable for us...
The other possibility is to set it to xsd:string and in the documentation explain that the implementation is free to define up to which level they want to support Xpath there and maybe define the minimum as we had before.
Javier.
On 3/3/06, "Döring, Markus" m.doering@bgbm.org wrote:
Well, what do you consider a proper xpath type? I think we can add some basic things to our simple pattern. But are you also thinking of adding different axes, functions and all this? Things I could see to be allowed are:
(pre:)qname Selects all child nodes named like this (optionally qualified with prefixes) / Selects from the root node // Selects nodes in the document from the current node that match the selection no matter where they are .. Selects the parent of the current node @ Selects attributes Predicates: [i] Select ith node [last()-1] Select second-last node [position()<3] Select all nodes before the third
But that already means we could get a list of matching nodes from the xpath. So a simple mapping becomes a mapping to a list of nodes - essentially multiple single mappings. Gregor was actually looking for this in the recursive SDD.
Is this overkill already? Markus
-----Ursprüngliche Nachricht----- Von: tdwg-tapir-bounces@lists.tdwg.org [mailto:tdwg-tapir-bounces@lists.tdwg.org] Im Auftrag von Javier privat Gesendet: Donnerstag, 2. März 2006 19:48 An: Renato De Giovanni Cc: tdwg-tapir@lists.tdwg.org Betreff: Re: [tdwg-tapir] conceptual binding
Hi,
Now looking at the "simpleXPathType" (used by the node's path attribute) it seems that the string restriction does not allow for namespace prefixes. So I guess this is something that needs to be fixed in the schema.
Actually the problem with the simpleXpathType arise when I did the example outputModel, it does not validate against the schema because I used ns prefixes.
Maybe my sentence was incorrect, I wanted to say "The change in the mapping section is only in allowing (forcing?) qualifies paths in the node element"
Actually I think pywrapper would not complain of the lack of ns prefixes there (probably the other way around :D ), but in the unlikely event that the ns resolve ambiguities then we are in troubles.
And actually I don't know why this path can not be an xpath. pywrapper and Digir will not be able to undertand complicate xpaths, but maybe other implementations can, and I don't see what is the problem if the provider arise and error like "Sorry xpath in the mapping section of the outputModel not understood".
Imagine a TAPIR implementation that allows you to do a mapping to the second element </a>using xpath expressions. We would be able to do mappings to structures like:
<a> <b/> <b>content here</b> </a>
So here is my proposal: change the simpleXPathType to a proper XpathType.
Javier.
Best Regards,
Renato
On 2 Mar 2006 at 17:11, Javier de la Torre wrote:
Uhmm...
Did I understand this incorrectly? The change in the mapping would only be qualifying concepts in the path attribute not in the concept ids.
I think we agree on that the concept ids does not have anything to do with XML schema or Xpaths no? Is just "by coincide" that we are using something "similar".
Javier.
On 3/3/06, Renato De Giovanni renato@cria.org.br wrote:
Hi Markus,
This is really good news for the PyWrapper!
Now concerning your question, I think we should really try to avoid defining concepts with compound XML schemas. It's a lot cleaner and more elegant using gcp#accession/FullScientificName to map local databases and to use in filters. As you said, the WFS response would just be one of the possible output models making use of the concepts.
The real xpaths to WFS elements (including namespaces) would only be used in the output model mapping section:
<node path="/wfs:FeatureCollection/gml:featureMember/gcp:accession/ gcp:FullS cientificName">
<concept id="gcp#accession/FullScientificName"/> </node>
Best Regards,
Renato
On 28 Feb 2006 at 11:38, "Döring, Markus" wrote:
Hello, I recently added support for schema imports in pywrapper mainly to support multiple namespaces in the repsonse. Me (and Javier) wanted to allow something like this:
<wfs:FeatureCollection xmlns:wfs="http://www.opengis.net/wfs" xmlns:gml="http://www.opengis.net/gml" xmlns:gcp="http://www.ipgri.org/schemas/gcp_passport_gml/1.0%22%3E gml:featureMember <gcp:accession fid="accession.12"> gcp:GermplasmID12</gcp:GermplasmID> gcp:FAOInstituteCodeES</gcp:FAOInstituteCode> gcp:FullScientificNameQuercus ilex</ gcp:FullScientificName> </gcp:accession> </gml:featureMember> </wfs:FeatureCollection>
Here comes my problem: How do we refer to the FullScientificName concept in TAPIR?
As a convention for schemas we said to create the fully qualified concept from the namespace and the simple xpath to the element. So somethinkg like this:
http://www.opengis.net/wfs#/FeatureCollection/featureMember/ accession/FullScientificName
A real xpath to that element would of course include several namespaces: /wfs:FeatureCollection/gml:featureMember/gcp:accession/ gcp:FullScientificName
Could it be that we never need to refer to "compound" concepts anyway? A provider would probably map his db to the GCP schema alone. The WFS response is only the responded view/data model and we would still just use gcp#accession/FullScientificName as the qualified concept in filters. This is also true for our simple extension schemas I think (EFG for ABCD, all extensions for DwC). But arent there other cases?
Thanks, Markus
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