Which of the following is true about XML columns?

A.
XML columns are used to store XML documents as a hierarchical set of entities

B.
OnlyXQuery can be used to retrieve an XML document from an XML column

C.
XML columns must be altered to accommodate additional parent/child relationships if they are
used in referential constraints

D.
In order to access any portion of an XML document stored in an XML column, the entire
document must be retrieved