On February 11 2007, Yaron Koren wrote: > There was an email thread around the first week of January on the > subject of declaring "enum" types, meaning types that should have one of > a fixed set of values. There were two ways noted to declare such a type: > > 1) In the field's "attribute" page, have a tag reading: > > [[possible values:=value1,value2,value3]]
That's what I checked in to Subversion and it's now running on ontoworld.org, see http://ontoworld.org/wiki/Type:Enumeration and http://ontoworld.org/wiki/Test_Enumeration, but it's not guaranteed to be in released SMW 0.7. Pro: simple Con: you hit the string size limit really quickly harder to control numeric values values can't have commas in them without an escape syntax > 2) In the field's "type" page, have tags reading: > > [[Enum mapping:=value1=1]] > [[Enum mapping:=value1=2]] > [[Enum mapping:=value1=3]] That's what Ittay Dror implemented, and sent in the patch to SMW-devel. > Which of these is recommended/supported? Or is it both? (In theory, > there's no conflict between the two.) I still mean to install his patch locally and compare. > Tied in to this is the more general question of whether descriptive > information like this should be stored in "attribute" or "type" pages. I > suspect this question will get more important as SMW gains more > structured features, like, say, OWL exporting, and forms for editing > data (I'm working on something involving the second one). > > I can think of good arguments either way: > - if you put the data in "attribute" pages, you don't have to create a > custom type for each field that you want special handling for. > - if you put the data in "type" pages, you can have special handling for > relations, not just attributes (if you ever needed such a thing). I don't understand. Relations don't have types. (SMW currently has almost no error handling for special properties like [[has type]] , so you can slap them on any page and they'll show up in the factbox even though only certain namespaces make use of them. Seems like a bug, though it makes playing around easy :-) ) > Also, > you could have different attributes for the same type, with all the same > properties (if don't know if you'd ever need that either). Yes, you could have a Type:Severity and then use it for Attribute:Bug_severity, Attribute:Torture_level, Attribute:Scale_of_natural_disaster, etc. That might be useful but why not just separate attributes? Some other things to consider: * An attribute can "refine" handling of a type. Currently floats can specify the units to display, and by overloading display units, booleans and dates can control display format. * You can't currently query against the underlying type. * One type can't extend another -- [[Has Type::Type:Foo]] doesn't work for types. > Does anyone have any thoughts on this? -- =S Page ------------------------------------------------------------------------- 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
