PostgreSQL is an object-relational database management system (ORDBMS) based on
POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer
Science Department. POSTGRES pioneered many concepts that only became available in some
commercial database systems much later.
Features PostgreSQL is an open-source descendant of this original Berkeley code. It
supports SQL92 and SQL99 and offers many modern features:
complex queries
foreign keys
triggers
views
transactional integrity
multiversion concurrency control
Additionally, PostgreSQL can be extended by the user in many ways, for exampleby
adding new

data types
functions
operators
aggregate functions
index methods
procedural languages
And because of the liberal license, PostgreSQL can be used, modified, and distributed by
everyone free of charge for any purpose, be it private, commercial, or academic.

Advantages PostgreSQL offers many advantages for your company or business over other
database systems.
1) Immunity to over-deployment
Over-deployment is what some proprietary database vendors regard as their #1 licence
compliance problem. With PostgreSQL, no-one can sue you for breaking licensing agreements,
as there is no associated licensing cost for the software.
This has several additional advantages:
More profitable business models with wide-scale deployment.
No possibility of being audited for license compliance at any stage.
Flexibility to do concept research and trial deployments without needing to include
additional licensing costs.
2) Better support than the proprietary vendors
In addition to our strong support offerings, we have a vibrant community of PostgreSQL
professionals and enthusiasts that your staff can draw upon and contribute to.
3) Significant saving on staffing costs
Our software has been designed and created to have much lower maintenance and tuning
requirements than the leading proprietary databases, yet still retain all of the features, stability,
and performance.
In addition to this our training programs are generally regarded as being far more cost
effective, manageable, and practical in the real world than that of the leading proprietary database
vendors.
4) Legendary reliability and stability
Unlike many proprietary databases, it is extremely common for companies to report that
PostgreSQL has never, ever crashed for them in several years of high activity operation. Not
even once. It just works.
5) Extensible
The source code is available to all at no charge. If your staff have a need to customise or
extend PostgreSQL in any way then they are able to do so with a minimum of effort, and with no
attached costs. This is complemented by the community of PostgreSQL professionals and
enthusiasts around the globe that also actively extend PostgreSQL on a daily basis.
6) Cross platform
PostgreSQL is available for almost every brand of Unix (34 platforms with the latest stable
release), and Windows compatibility is available via the Cygwin framework. Native Windows
compatibility is also available with version 8.0 and above.
7) Designed for high volume environments
We use a multiple row data storage strategy called MVCC to make PostgreSQL extremely
responsive in high volume environments. The leading proprietary database vendor uses this
technology as well, for the same reasons.
8) GUI database design and administration tools

Several high quality GUI tools exist to both administer the database (pgAdmin, pgAccess)
and do database design (Tora, Data Architect).

1, teller  ['telə]
n. （美）出纳员；讲述者；讲故事者；计票员

2, reservation  [,rezə'veiʃən]
n. 预约，预订；保留
3, at will 
随意；任意
4, pioneer  [,paiə'niə]
n. 先锋；拓荒者
vt. 开辟；倡导；提倡
vi. 作先驱

5, proprietary  [prə'praiətəri]
a. 专利的(所有的)
n. 所有权(所有人)

6, globe  [gləub]
n. 地球,地球仪,球体

7, volume  ['vɔlju:m; (US) -jəm]
n. 体积,容量,音量
n. 卷,册