The DatasetMap, ConfigurationMap and LanguageMap elements of a WS-DAI property document each have the attributes 
minOccurs=1 and maxOccurs=unbounded.

However:

The ConfigurationMap properties are not required for resources which do not implement factory operations.

LanguageMap properties are not required for data resources that do not support the execution of expressions. For example
, a resource accessed through the XMLSequenceAccess port type allows only one operation, getItems, which does not 
require a query expression.

It may also be possible to define resources which do not require the DatasetMap property.

It is therefore suggested that these three properties are made optional. .