Annotated XML schema decomposition offers decomposition keywords for use
in the db2-xdb:condition and db2-xdb:expression annotations.
- $DECOMP_CONTENT
- The value of the mapped XML element or attribute from the document,
constructed according to the setting of the db2-xdb:contentHandling annotation. The value
replaced for $DECOMP_CONTENT in the expression should always be considered
a character type. Refer to the limits and restrictions documentation for the
maximum string length of and maximum number of $DECOMP_CONTENT instances
supported. If db2-xdb:expression specifies $DECOMP_CONTENT and db2-xdb:normalization is
specified in the same mapping, then the $DECOMP_CONTENT value for db2-xdb:expression will
be normalized before it is passed to the expression for evaluation, if applicable.
$DECOMP_CONTENT can be used to process the value of the mapped element
or attribute, using customized expressions, rather than directly inserting
that value.
- $DECOMP_DOCUMENTID
- The string value specified in the documentid input parameter
of the xdbDecompXML stored procedure, which identifies the XML document being
decomposed. When the document is decomposed, the input value provided to
the xdbDecompXML stored procedure is used as the value substituted for $DECOMP_DOCUMENTID.
Applications can pass into xdbDecompXML, uniquely generated document
IDs. These IDs can then be directly inserted into the database. The IDs
can also be passed into expressions that generate unique identifiers for elements
or attributes. $DECOMP_DOCUMENTID can be used, therefore, to insert
unique identifiers that are not present in the XML document.
- $DECOMP_ELEMENTID
- A system-generated integer identifier that uniquely identifies within
the XML document, the element or attribute this annotation describes. This
value will remain unchanged between decomposition operations for the same
XML document, as long as the document does not change in any of the following
ways: element addition, element deletion, or a change in an element's position
in document order. If the document is modified in these ways and decomposed
again, elements might not have the same identifier as they did following the
previous decomposition. $DECOMP_ELEMENTID specified on an attribute
is defined to be the value of the $DECOMP_ELEMENTID for the element
to which this attribute belongs.
The value generated by $DECOMP_ELEMENTID
can also be used to indicate the order of elements in the original document.
This can be useful in cases where the XML document needs to be re-composed
from relational tables.
DB2 Version 9.7 for Linux, UNIX, and Windows