SQL Bible [Electronic resources] نسخه متنی

Summary

New developments like XML, OLAP, and
object-oriented technologies continue to change the ways we are collecting,
storing, and consuming information; the very nature of the information keeps
changing and often involves new media and new formats.

XML emerged as the de-facto information
exchange standard and not surprisingly, relational databases responded by
incorporating XML into their cores. The approaches taken by each of the RDBMS
vendors might be different (XML documents might be mapped and parsed in
familiar text-based records, or be stored as complete documents), but the
details of these implementations have become increasingly irrelevant to the
vast majority of developers and users.

OLAP became a standard for BI — business
intelligence. With the enormous amount of data — structured or otherwise —
accumulated since the dawn of civilization, it was only a matter of time before
someone would take data comprehension to the next level, which is to discover
statistical trends. While not part of the RDBMS technology, BI does not make
much sense without some kind of a database — relational, in our case. The main
processing unit of this information is a multidimensional CUBE, which can be
manipulated using either some general-purpose language (like Java) or some
proprietary language (like Microsoft MDX). Some vendors bundle business
intelligence tools with their RDBMS, some BI tools are stand-alone tools built
by third-party companies.

The object-oriented approach became the
de-facto application programming standard, and as such made a compelling case
for object-oriented databases. As we model the surrounding world in terms of
objects, we need a place to store these objects. An RDBMS maps the objects to
words; an OODBMS will accept them as they are. You may compare it to a book,
where images are created by your brain from mere words; the movie stores and
communicates visual objects directly to your senses, bypassing the
verbalization step.

OODBMS may well be the wave of the future,
which is notoriously unpredictable. As of today, many companies have
implemented object-oriented databases, designed to store and retrieve objects
created within some particular language (Java, C++, Smalltalk). Eventually, new
standards will emerge and performance gaps — if any — will be eliminated,
making RDBMS outdated. For now, RDBMS remain the pillars of the business
community, though they do pay lip service to the objects, incorporating them as
data types but warning against the inefficiency of using them.