Schema Evolution for XML: A Consistency-Preserving Approach

Regular expression transformations to extend regular languages (with application to a Datalog XML schema validator)

“…We recall that GREC (firstly introduced in [3]) is an extension of the reduction process proposed in [4] to transform a Glushkov automaton into a regular expression. This process is based on the application of four reduction rules: different rules are applied whether two nodes are "connected" by an and or an or; whether a node is optional or is part of a closure.…”

“…Positions (e.g., 1.0, 2.0.1, 10.0.1) are elements of a tree domain. 3 Each position is associated to a label corresponding to an element name in the XML document. For instance, in Fig.…”

“…When all the nodes of a tree respect their schema constraints we say that the tree is valid. In this context, the following example (adapted from [3]) illustrates the schema evolution as proposed by our method. As our user is a data administrator, the requested update will be taken as a request to change the schema.…”

“…The algorithm GREC, 1 proposed in [3], deals with the same problem and proposes an algorithm which works on the automaton M E associated to E: It performs changes on M E in order to obtain new automata M , for which regular expressions E are generated. The algorithm GREC is an extension of the reduction process proposed in [4] (to transform a Glushkov automaton into a regular expression).…”

On Different Perspectives of XML Data Evolution

“…to so-called extensional level, to ensure that XML documents are valid against the evolved XML schema. There also exists an opposite approach that enables to evolve XML documents and propagate the transformations to their XML schema [3].…”