More than just class and properties?


I'm working for a CMS vendor and I'm currently studying the use of RDFa to add meta data to the pages generated by our product to provide a front end editing interface to our users. The idea is to generate pages together with some meta information and let a JavaScript component read those information to generate a nice end user interface that allow to interact with the content, something quite similar to but more sophisticated. So I need identify for instance the title, the author, the content, ... of the articles stored in the CMS, but I also need to add some others meta data and this is where I don't know how I should proceed. For instance, let say I have something like:

<body xmlns:myclasses="">
 <article class=”main-page-article” typeof="myclasses:Article" about="/A-big-title">
   <h1 property="myclasses:title">A big title</h1>
   <p class="summary" property="myclasses:summary">A small summary, lorem ipsum</p>
   <!-- ... -->

how can I express that the property myclasses:title should not be longer than 250 characters or that the current user is able to edit it but not myclasses:title or how can I express that internally the title is stored as a string while the subtitle is stored as "text" (longer datatype, line feed are accepted, ...)


Make your own properties to specify all this. For instance

myclasses:title myclasses:maxLength 250 .
myclasses:title myclasses:editableBy myclasses:userGroupA .
myclasses:title myclasses:internalDataType myclasses:String .
myclasses:subtitle myclasses:internalDataType myclasses:Text .

"Anyone can say anything about any topic" means it's OK to coin new properties when the standard ones won't do.

+1 @database_animal 's suggestion for custom properties

There are other methods - eg. range an xsd custom datatype with a maxLength restriction ( W3Cs ACL Ontology for authorisation (

It's worthwhile to consider the tradeoff of standardisation vs. ease of implementation vs value added.

RDFAuthor ( and Ontowiki ( are probably worth checking out from a general javascript RDFa editing viewpoint