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RDF Container Elements

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RDF containers are used to describe group of things. For example, to list the authors of a book or to list the members in a band.

The following RDF elements are used to describe such groups: <Bag>, <Seq>, and <Alt>.

The <rdf:Bag> Element

The <rdf:Bag> element is used to describe a list of values that is intended to be unordered.

The <rdf:Bag> element may contain duplicate values.

Example

<?xml version="1.0"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" 
xmlns:cd="http://www.recshop.fake/cd#"> 
<rdf:Description
 rdf:about="http://www.recshop.fake/cd/Beatles">
 <cd:artist>
   <rdf:Bag>
     <rdf:li>John</rdf:li>
     <rdf:li>Paul</rdf:li>
     <rdf:li>George</rdf:li>
     <rdf:li>Ringo</rdf:li>
   </rdf:Bag>
  </cd:artist>
</rdf:Description>
</rdf:RDF>

The <rdf:Seq> Element

The <rdf:Seq> element is used to describe a list of values that is intended to be ordered (For example, in alphabetical order).

The <rdf:Seq> element may contain duplicate values.

Example

<?xml version="1.0"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" 
xmlns:cd="http://www.recshop.fake/cd#"> 
<rdf:Description
 rdf:about="http://www.recshop.fake/cd/Beatles">
 <cd:artist>	
   <rdf:Seq>
     <rdf:li>George</rdf:li>
     <rdf:li>John</rdf:li>
     <rdf:li>Paul</rdf:li>
     <rdf:li>Ringo</rdf:li>
   </rdf:Seq>
  </cd:artist>
</rdf:Description>
</rdf:RDF>

The <rdf:Alt> Element

The <rdf:Alt> element is used to describe a list of alternative values (the user can select only one of the values).

Example

<?xml version="1.0"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" 
xmlns:cd="http://www.recshop.fake/cd#"> 
<rdf:Description
 rdf:about="http://www.recshop.fake/cd/Beatles">
 <cd:format>	
   <rdf:Alt>
     <rdf:li>CD</rdf:li>
     <rdf:li>Record</rdf:li>
     <rdf:li>Tape</rdf:li>
   </rdf:Alt>
  </cd:format>
</rdf:Description>
</rdf:RDF>

RDF Terms

In the examples above we have talked about "list of values" when describing the container elements. In RDF these "list of values" are called members.

So, we have the following:

  • A container is a resource that contains things
  • The contained things are called members (not list of values)
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