RDF container elements

The RDF container is used to describe a set of things. For example, list the authors of a book together.

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

The <rdf:Bag> element

The <rdf:Bag> element is used to describe a list of values that are defined as unordered.

<rdf:Bag> Elements can 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 are defined as ordered (for example, an alphabetical sorting).

<rdf:Bag> Elements can 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 for a list of alternative values (the user can choose only one of these 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 above example, we have discussed 'value lists' when describing container elements. In RDF, these 'value lists' are called members (members).

Therefore, we can say that:

  • A container is a resource that contains things
  • The things included are called members (they cannot be called 'value lists').