From: Alexander Moshchuk (anm@cs.washington.edu)
Date: Mon Apr 26 2004 - 01:19:03 PDT
Of Objects and Databases: A Decade of Turmoil
The paper provides a survey of the work related to incorporating
object-oriented support into traditional database systems. The
authors identify four main approaches to this problem, and tell us how
well the approaches fared during the decade before the paper's
publication.
In extended RDBMS, known as object-relational databases today, we
start with a traditional RDMBS and SQL and add support for objects to
both of these. The objects can be defined as user-defined ADTs along
with an implementation in an external language, or row types, an
extension for tuples. The authors advocate this approach as the
winner among the rest - major commercial vendors are pushing in this
direction because they can extend their existing RDBMS technology
rather than commit to a new system.
The other three approaches have been less successful. Unlike the
previous one, they all involve adopting a new system. Persistent
programming languages add features to support data persistence and
atomic program execution. Although active in academia, they don't
have any commercial implementations, leading authors to declare it as
a dead-end. Another casualty is the database system toolkit approach.
Here, similarly to the idea of microkernels for OS design, we keep a
set of core DMBS facilities which can be extended at any level to
provide domain-specific functionality. This proved to be inflexible,
awkward, and too hard to use. The final approach - Object-Oriented
Database Systems - basically redesigns a DMBS in an object-oriented
fashion; this can be viewed as essentially adding database
functionality into an OO language. OODB failed to live up to
commercial expectations, with problems like no agreement on standards
and some functionality that lags behind RDBMS.
I thought the paper was interesting to read, and all of the arguments
seemed plausible. The paper assumes an understanding of the outlined
approaches, so sometimes I felt they could have given more background
for those not as familiar with the topic. I don't have enough DB
knowledge to tell if the authors' predictions for the next ten years
indeed came true, but it seems ORDB hasn't yet taken over the world.
In any case, the authors obviously missed the emerging importance of
the internet and related services in their vision of the future.
Also, they wrote their evaluation from a highly commercial standpoint,
where success of an idea ultimately depends only on a major vendor
implementing the idea.
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