Incremental validation of XML documents

Abstract

We investigate the incremental validation of XML documents with respect to DTDs, specialized DTDs, and XML Schemas, under updates consisting of element tag renamings, insertions, and deletions. DTDs are modeled as extended context-free grammars. "Specialized DTDs" allow the decoupling of element types from element tags. XML Schemas are abstracted as specialized DTDs with limitations on the type assignment. For DTDs and XML Schemas, we exhibit an O(m log n) incremental validation algorithm using an auxiliary structure of size O(n), where n is the size of the document and m the number of updates. The algorithm does not handle the incremental validation of XML Schema wrt renaming of internal nodes, which is handled by the specialized DTDs incremental validation algorithm. For specialized DTDs, we provide an O(m log 2 n) incremental algorithm, again using an auxiliary structure of size O(n). This is a significant improvement over brute-force re-validation from scratch.We exhibit a restricted class of DTDs called local that arise commonly in practice and for which incremental validation can be done in practically constant time by maintaining only a list of counters. We present implementations of both general incremental validation and local validation on an XML database built on top of a relational database.Our experimentation includes a study of the applicability of local validation in practice, results on the calibration of parameters of the auxiliary data structure, and results on the performance comparison between the general incremental validation technique, the local validation technique, and brute-force validation from scratch.

Deciding Definability by Deterministic Regular Expressions

“…The set Q of states is the disjoint union of the vertices V of G, plus two distinguished states q 0 (which is D's initial state) and q f (which is D's only accepting state). The alphabet Σ is defined as (V {q 0 , q f }) 2 . The transitions of D are defined as follows.…”

“…Primarily, schema information is crucial for automatic error detection in the data itself (which is called validation, see, e.g., [5,26,2,20]) or in the procedures that transform the data [24,23,22]. Furthermore, schemas provide information for optimization of XML querying and processing [25,28], they are inevitable when integrating data through schema matching [1], and they provide users with a high-level overview of the structure of the data.…”

XML document-grammar comparison: related problems and applications

“…The basic idea adopted in this family of methods [9,10,14,24,45,79] is to abstract DTDs/XSDs as extended Context-Free Grammars (CFG).…”

On Finding an Edit Script between an XML Document and a DTD

“…2 (b)). However, we cannot add such an address node because of (2). Hence there is no edit script between t and D.…”

“…G(t, j, k) exactly covers all the patterns of children of n i ; that is, ( 1 ) for every edit script s for t (not deleting n i ), G(t, j, k) contains a path from m j−1 to m k that represents ch(s(t), n i ), and ( 2 ) for every path p from m j−1 to m k in G(t, j, k), there exists an edit script s for t such that ch(s(t), n i ) is represented by p. Similarly, for every siblings n j , n k with j ≤ k, G (t, j, k) exactly covers all the patterns of children of n j,k . Proof(sketch): Condition (1) can easily be shown by induction on the length of s. As for Condition (2), let p be a path from m j−1 to m k in G(t, j, k). Let s be an edit script obtained from p by replacing (i) each leaf edge Step 3 We first show some definitions related to NFA, which is necessary to determine if a path in G(t, j, k) or G (t, j, k) from m j−1 to m k , representing a sequence of children of a node, matches a regular expression.…”