Communities will not want to reinvent the wheel every time they need a new attribute. Attributes must be able to be shared between communities. An important part of sharing is the identification of the origin and definition of the attributes in a query. Identifying the source of attributes also allows attributes from different communities to be mapped. For example, an application can know that Dublin Core Creator is the same as GILS Author and map a Dublin Core query onto a GILS database.
Attributes tell the server how to interpret the values given in the query.
There are a number of categories of attributes that an information community may wish to define. Interoperability and Extensibility. This allows a base level of interoperability across metadata repositories. Information communities should obviously be allowed to extend on this base set of attributes for their private use. Discovery of Attributes.