S Page wrote:
> Ittay Dror wrote:
>
> > can i create an attribute whose type is some enumeration?
>
> Not yet, but you join the list of people asking for this feature.
>
> I should be coding better date/time handling :-)
> but this is pretty straightforward; I've got an implementation working
> locally and should be able to check it into SVN tomorrow if no one objects.
>
> > the point is to have an attribute that accepts string values, but
> > still be able to create order, and use comparisons in queries.
> >
> > my use case is a 'product_version' attribute. I'd like for different
> > components to state since what product version they exist ('since
> > version 1.2'). i want then to be able to list all components for a
> > given version (something like [[product_version:=<1.3]]).
>
> The inline query code would have to detect queries on the enumerated
> datatype, look up the value_num for 1.3, and query on that. I don't
> have that part working.
can it be done by using special properties, like for the linear type handler
(conversions) property. the conversions will be from labels to numbers, rather
than factors to units.
>
> > version names can be anything (e.g. 'xp'). so i want to be able to
> > map them in the attribute page (or type of). then i'd assign to 1.1
> > the value of 1, to 1.2 the value of 2, to 'xp' the value of 3, etc.
>
> In my "keep it simple" approach, the [[Attribute:Product version]] page
> would have the special property
> [[possible values:=3.0,3.1,98,98SE,ME,XP,Vista]]
> and each comma-separated value gets a numeric offset that you wouldn't
> be able to control (or see).
>
> > when new versions come (incl. minor versions), i'll update the page,
> > inserting the version and its sequence number (maybe bumping others)
>
> In my "keep it simple" approach, if you inserted a new value within
> possible values, you'd have to re-edit all pages with the attribute to
> update the offsets. If you really want an advanced enum type that lets
> you control the numeric value of each string, how would you specify this
> in wiki text?
>
> In another message, Ittay Dror wrote:
> > can anyone please give pointers (or example code) how to
> > implement as custom type (php)?
> My PHP code for SMWEnumeratedTypeHandler is a combination of
> SMWStringTypeHandler and SMWBooleanTypeHandler, with handling of the
> special property "possible values" similar to "display units". Nothing
> innovative ;-)
>
> Notes
> -----
> I don't think there's any way to represent an enumerated type in RDF
> export beyond the string XSD type.
>
> Although strings are the obvious case for enumeration, [[possible
> values]] could also be applied to other attribute datatypes, and even to
> relations. But no one's asked for that yet.
>
> The [[possible values]] special property will really run into the 255
> character limit for string values. But if you split the enumeration
> across two [[possible value]] attributes, I don't think order is
> guaranteed between them.
>
> --
> =S
>
--
===================================
Ittay Dror,
Chief architect,
R&D, Qlusters Inc.
[EMAIL PROTECTED]
+972-3-6081994 Fax: +972-3-6081841
www.openqrm.org - Data Center Provisioning
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Semediawiki-user mailing list
Semediawiki-user@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/semediawiki-user
