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PostgreSQL is an open source relational database management system that began as a
University of California, Berkeley project. It was originally under the BSD license, but
is now called the PostgreSQL License (TPL). For all intents and purposes, it’s BSD
licensed. It has a long history, almost dating back to the beginning of relational databases.
It has enterprise class features such as SQL windowing functions, the ability to create
aggregate functions and also utilize them in window constructs, common table and
recursive common table expressions, and streaming replication. These features are
rarely found in other open source database platforms, but commonly found in newer
versions of the proprietary databases such as Oracle, SQL Server, and IBM DB2. What
sets it apart from other databases, including the proprietary ones we just mentioned,
is the ease with which you can extend it without changing the underlying base—and
in many cases, without any code compilation. Not only does it have advanced features,
but it performs them quickly. It can outperform many other databases, including proprietary
ones for many types of database workloads.
In this book, we’ll expose you to the advanced ANSI-SQL features that PostgreSQL
offers. and the unique features PostgreSQL has that you won’t find in other databases.
If you’re an existing PostgreSQL user or have some familiarity with PostgreSQL, we
hope to show you some gems you may have missed along the way; or features found
in newer PostgreSQL versions that are not in the version you’re using. If you have used
another relational database and are new to PostgreSQL, we’ll show you some parallels
with how PostgreSQL handles tasks compared to other common databases, and
demonstrate feats you can achieve with PostgreSQL that are difficult or impossible to
do in other databases. If you’re completely new to databases, you’ll still learn a lot about
what PostgreSQL has to offer and how to use it; however, we won’t try to teach you
SQL or relational theory. You should read other books on these topics to take the
greatest advantage of what this book has to offer.
This book focuses on PostgreSQL versions 9.0 to 9.2, but we will cover some unique
and advanced features that are also present in prior versions of PostgreSQL. |
