2008 VLDB: “Managing and querying transaction-time databases under schema evolution”

 “Managing and querying transaction-time databases under schema evolution”   H. J. Moon, C. A. Curino, A. Deutsch, C.-Y. Hou, and C. Zaniolo. Very Large Data Base VLDB, 2008. 

The old problem of managing the history of database information is now made more urgent and complex by fast-spreading web information systems. Indeed, systems such as Wikipedia are faced with the challenge of managing the history of their databases in the face of intense database schema evolution. Our PRIMA system addresses this difficult problem by introducing two key pieces of new technology. The first is a method for publishing the history of a relational database in XML, whereby the evolution of the schema and its underlying database are given a unified representation. This temporally grouped representation makes it easy to formulate sophisticated historical queries on any given schema version using standard XQuery. The second key piece of technology provided by PRIMA is that schema evolution is transparent to the user: she writes queries against the current schema while retrieving the data from one or more schema versions. The system then performs the labor-intensive and error-prone task of rewriting such queries into equivalent ones for the appropriate versions of the schema. This feature is particularly relevant for historical queries spanning over potentially hundreds of different schema versions. The latter one is realized by (i) introducing Schema Modification Operators (SMOs) to represent the mappings between successive schema versions and (ii) an XML integrity constraint language (XIC) to efficiently rewrite the queries using the constraints established by the SMOs. The scalability of the approach has been tested against both synthetic data and real-world data from the Wikipedia DB schema evolution history. 

 

For more information on this project visit: http://yellowstone.cs.ucla.edu/schema-evolution/index.php/Prima

2008 VLDB: “Graceful database schema evolution: the prism workbench”

  “Graceful database schema evolution: the prism workbench” Carlo A. Curino, Hyun J. Moon, and Carlo Zaniolo. Very Large Data Base VLDB, 2008 PDF

Supporting graceful schema evolution represents an unsolved problem for traditional information systems that is further exacerbated in web information systems, such as Wikipedia and public scientific databases: in these projects based on multiparty cooperation the frequency of database schema changes has increased while tolerance for downtimes has nearly disappeared. As of today, schema evolution remains an error-prone and time-consuming undertaking, because the DB Administrator (DBA) lacks the methods and tools needed to manage and automate this endeavor by (i) predicting and evaluating the effects of the proposed schema changes, (ii) rewriting queries and applications to operate on the new schema, and (iii) migrating the database.

Our PRISM system takes a big first step toward addressing this pressing need by providing: (i) a language of Schema Modification Operators (SMO) to express concisely complex schema changes, (ii) tools that allow the DBA to evaluate the effects of such changes, (iii) optimized translation of old queries to work on the new schema version, (iv) automatic data migration, and (v) full documentation of intervened changes as needed to support data provenance, database flash back, and historical queries. PRISM solves these problems by integrating recent theoretical advances on mapping composition and invertibility, into a design that also achieves usability and scalability. Wikipedia and its 170+ schema versions provided an invaluable testbed for validating PRISM tools and their ability to support legacy queries.

 For more details and an on-line DEMO of the system visit:  http://yellowstone.cs.ucla.edu/schema-evolution/index.php/Prism

Bibtex:

@INPROCEEDINGS{curino-vldb2008a,
author = {Carlo A. Curino and Hyun J. Moon and Carlo Zaniolo},
title = {Graceful database schema evolution: the prism workbench},
booktitle = {Very Large Data Base (VLDB)},
year = {2008}
}
 

 

2008: Information Systems Integration and Evolution: Ontologies at Rescue

“Information Systems Integration and Evolution: Ontologies at Rescue”, Carlo A. Curino, Letizia Tanca, Carlo Zaniolo International Workshop on Semantic Technologies for System Maintenance (STSM) 2008

The life of a modern Information System is often char-
acterized by (i) a push toward integration with other sys-
tems, and (ii) the evolution of its data management core
in response to continuously changing application require-
ments. Most of the current proposals dealing with these is-
sues from a database perspective rely on the formal notions
of mapping and query rewriting. This paper presents the
research agenda of ADAM (Advanced Data And Metadata
Manager); by harvesting the recent theoretical advances in
this area into a unified framework, ADAM seeks to deliver
practical solutions to the problems of automatic schema
mapping and assisted schema evolution. The evolution of
an Information System (IS) reflects the changes occurring in
the application reality that the IS is modelling: thus, ADAM
exploits ontologies to capture such changes and provide
traceability and automated documentation for such evolu-
tion. Initial results and immediate benefits of this approach
are presented.

 

2008 Information Systems Integration and Evolution: Ontologies at Rescue

“Information Systems Integration and Evolution: Ontologies at Rescue”, Carlo A. Curino, Letizia Tanca, Carlo Zaniolo International Workshop on Semantic Technologies for System Maintenance (STSM) 2008

The life of a modern Information System is often characterized by integration with other systems, and continuous evolution of their data management core, to face unexpected changes in its requirements. Most of the solutions dealing with these issues from a database perspective rely on the notions of mapping and query rewriting. This paper presents the research agenda of ADAM (Advanced Data And Metadata Manager), a unified framework which, harvesting recent theoretical advances in this area, will deliver practical solutions for automatic schema mapping and graceful schema evolution. Information Systems evolution reflects changes in the model of their business reality; in the ADAM project we exploit ontologies to capture such changes in order to provide traceability and documentation of the evolution. Initial results and immediate benefits of this approach are presented.

 

Paper available at: curino-STSM08-CR.pdf

FlyMake Emacs: continuous compilation

This youtube video shows the possibility of using Emacs with a “continuous” compilation feature turned on… it is horribly slow, since the guys who made it do not talk, but only type 🙁 so feel free to skip all the way to 4′:30” (out of 5′) to see the interesting part. Sounds good to me…

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PRISM: a tool for schema evolution


 

 

I just posted on-line a Demo (work in progress) of a tool for Schema Evolution support i designed and implemented during my stay in UCLA under the guidance of Carlo Zaniolo and with the collaboration of Hyun J. Moon.

 Feel free to test it, criticize it, and report me feedback of any kind: Prism a tool for schema evolution (http://yellowstone.cs.ucla.edu/schema-evolution/index.php/PrismDemo)

 A Video of a typical interaction with the interface is available at: Prism a tool for schema evolution (http://yellowstone.cs.ucla.edu/schema-evolution/documents/Prism-Demo.mov)

 Let me know your opinions …