(2/1/00) Investigate the reasonable way to do XML updates:



Representing changes in semistructured data. Query language Chorel could query over data and changes represented in DOEM. System implemented in Lorel system.

Update on OEM model: node insertion, update of node values, and addition and removal of labeled arcs.

DOEM: Use tags to annotate the changes on each node. There are four kinds of annotations corresponding to fours updates: cre(t), upd(t, ov), add(t), and rem(t).

In DOEM, every object has its oid, so the updates is easily described as the operations on the object.

In Charel, put <tag> before and after a label, to find the objects recently changed.


In OEM, there is no distinguish between data and schema, (as they are semistructured), so in terms of XML, they are handling only the well-formed XML documents.

They use OID to describe the changes, and using the tagged path expression in their queries..


XMLTreeDiff can compare two DOM structures (or XML documents) by just looking at the document structure, not the particular file representation of it. It reports the differences in XML format as a sequence basic of tree operations like change node, delete node and insert node. XMLTreeDiff provides an update tool as well, which will update a DOM by using a XML difference report, and a graphical user interface to display the differences on the DOM trees themselves.

They use [XPath] for syntax of location of a portion of XML data.

They have extend the DOM model to handle DTD related operations.


They consider three types of basic updates on web data source: Ins, Del and Chg. <Ins, o1, l, o2> and <Del, o1, l, o2>represent the insertion and deletion of the edge with label l from object o1 to object o2. <Chg, o, OldVal, NewVal>denotes the change of the value of the atomic object o from OldVal to NewVal. For both insertion and deletion, o1 must be a complex object while o2 can be either an atomic object or a complex one.

In terms of update propagation, they have following conclusions:


They still don't have DTD extensions.

(2/10/00) How XML updates and DTD updates related?:

How to synchronize XML documents transferred by XSLT?:


Synchronize An Index Structure for XQL query result (XML View) when the XML documents updated.