View update translation for XML

Abstract

We study the problem of update translation for views on XML documents. More precisely, given an XML view definition and a user defined view update program, find a source update program that translates the view update without side effects on the view. Additionally, we require the translation to be defined on all possible source documents; this corresponds to Hegner's notion of uniform translation. The existence of such translation would allow to update XML views without the need of materialization.The class of views we consider can remove parts of the document and rename nodes. Our update programs define the simultaneous application of a collection of atomic update operations among insertion/deletion of a subtree and node renaming. Such update programs are compatible with the XQuery Update Facility (XQUF) snapshot semantics. Both views and update programs are represented by recognizable tree languages. We present as a proof of concept a small fragment of XQUF that can be expressed by our update programs, thus allows for update propagation.Two settings for the update problem are studied: without source constraints, where all source updates are allowed, and with source constraints, where there is a restricted set of authorized source updates. Using tree automata techniques, we establish that without constraints, all view updates are uniformly translatable and the translation is tractable. In presence of constraints, not all view updates are uniformly translatable. However, we introduce a reasonable restriction on update programs for which uniform translation with constraints becomes possible.

Consistency and repair for XML write-access control policies

“…. , r j of the form 4. No deleted or replaced node (n i or m j ) is an ancestor of another of the modified nodes (n i , m j , l k ) 5.…”

“…Rules (3), (4) and (5) make sure that the repairs have no inconsistencies. Indeed, rule (3) ensures that if it is possible to insert and delete a certain element type, then all the operations below it should be allowed; rule (4) forces the replace graphs to be transitive; and rule (5) checks that if an element type belongs to a cycle, then everything is allowed below it. The denial constraint (6) makes sure that no operation is both allowed and denied in the repair.…”

“…Boneva et al [4] study the problem of safely propagating updates to XML security views back to uniform, sideeffect free updates to the original source document. This technique is complementary to our approach.…”

An expressive bidirectional transformation language for XQuery view update

“…The work [31] addresses the problem of updating XML source through XML views. However, only views that remove parts of the document and rename nodes are supported.…”

Updating Typical XML Views

“…Consequently view update techniques are still necessary. The work in [3] is on the exact topic as this paper, but it restricts its views only to node relabeling and selection; no restructuring is allowed in the view definitions.…”