2,156 research outputs found
Incremental materialization of object-oriented views
We present an approach to handle incremental materialization of object-oriented views. Queries that define views are implemented as methods that are invoked to compute corresponding views. To avoid computation from scratch each time a view is accessed, we introduce some deferred update algorithms that reflect for a view only related modifications introduced into the database while that view was inactive. A view is updated by considering modifications performed within all classes along the inheritance and class-composition subhierarchies rooted at every class used in deriving that view. To each class, we add a modification list to keep one modification tuple per view dependent on that class. Such a tuple acts as a reference point that marks the start of the next update to the corresponding view. © 1999 Elsevier Science B.V. All rights reserved
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The Application of Object-Oriented Views to an Engineering Environment.
With the increasing popularity of object-oriented technology, object-oriented database systems are being used in design environments as central repositories. In this thesis, we investigate the role of versioning and the characteristics of design databases in design environments. In an effort to improve the configuration management scheme in a design environment, we also investigate the use of database views as a possible configuration tool.
We propose a unified version management scheme that facilitates cooperative team work and show that the use of database views provides a powerful configuration management scheme for a design environment
Framework for Live Synchronization of RDF Views of Relational Data
This Demo presents a framework for the live synchronization of an RDF view defined on top of relational database. In the proposed framework, rules are responsible for computing and publishing the changeset required for the RDB-RDF view to stay synchronized with the relational database. The computed changesets are then used for the incremental maintenance of the RDB_RDF views as well as application views. The Demo is based on the LinkedBrainz Live tool, developed to validate the proposed framework
Incremental View Maintenance For Collection Programming
In the context of incremental view maintenance (IVM), delta query derivation
is an essential technique for speeding up the processing of large, dynamic
datasets. The goal is to generate delta queries that, given a small change in
the input, can update the materialized view more efficiently than via
recomputation. In this work we propose the first solution for the efficient
incrementalization of positive nested relational calculus (NRC+) on bags (with
integer multiplicities). More precisely, we model the cost of NRC+ operators
and classify queries as efficiently incrementalizable if their delta has a
strictly lower cost than full re-evaluation. Then, we identify IncNRC+; a large
fragment of NRC+ that is efficiently incrementalizable and we provide a
semantics-preserving translation that takes any NRC+ query to a collection of
IncNRC+ queries. Furthermore, we prove that incremental maintenance for NRC+ is
within the complexity class NC0 and we showcase how recursive IVM, a technique
that has provided significant speedups over traditional IVM in the case of flat
queries [25], can also be applied to IncNRC+.Comment: 24 pages (12 pages plus appendix
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