[Abstract] There are many database systems, and the database of free software PostgreSQL is a very complete free software object - the relationship database management system (ORDBMS), which is the predecessor of many commercial databases today. When the Linux system is popular, the PostgreSQL database system is also an efficient and stable database system that is suitable for your needs.
For more than a year, Linux's popularity is accelerating, and the discussion of Linux sections in each forum is also very fire, and the combination of Linux Apache PHP MySQL makes the mysql database very fire. In fact, there is also a more powerful database PostgreSQL in the database.
PostgreSQL is a very complex object-relational database management system (ORDBMS), is also the most powerful, most complete and most complex free software database system. Some characteristics do not even have business databases.
This database research program originated from Berkeley (BSD) has been derived into an international development project and has a very broad user.
PostgreSQL can be said to be the most distinctive free database management system, and even we can also be said to be the most powerful free software database management system. In fact, PostgreSQL features cover SQL-2 / SQL-92 and SQL-3 / SQL-99, first, it includes it can be said to be the most abundant data type in the world, some of which can be said The commercial database is not available, such as IP type and geometric type, etc .; Second, PostgreSQL is a full-featured free software database. For a long time, PostgreSQL is the only support system, subquery, multi-version parallel control system, data integrity check, etc. The only free software database management system for characteristics. Until recently had INTERBASE and SAP and other manufacturers have broken this unique after opening its original proprietary software to free software.
1. Install natural, you have to install it before you want to start using PostgreSQL. PostgreSQL is likely to be installed on your machine because it is included in your operating system, or the system administrator has installed it. If the Linux system, such as Redhat, TurboLinux selects the installation database system when installing, you have already installed PostgreSQL. If this is the case, you should get information from the operating system document or your system administrator how to access PostgreSQL information. If you don't know if postgreSQL is already installed, or don't know if you can use it (already installed) to do your own experiment, you can install it. It is not difficult to do this, and it is a good practice. PostgreSQL can be installed by any non-privileged user without the need for superuser (root). If you are ready to install your PostgreSQL, please refer to the administrator manual (here there is a Chinese document) to get the relevant information for the installation, and then return to this guide after installation. Be sure to follow the information about setting the appropriate environment variable as much as possible.
If your machine administrator does not set various parameters in the default manner, you still have a little extra live. For example, if the database server machine is a remote machine, you need to set the PGHOST environment variable to the name of the database server. Environment variables PGPORT may also be set. The last trick: If you try to start an app, you can't connect with the database, you should contact your database administrator immediately, if you are an administrator, then you will refer to the document to make sure you The environment variable gets the correct setting. 2. The basic concept of the system should first understand the basic system of the PostgreSQL system before we start explaining. It is understood that the interrelationship between the POSTGRESQL components will be clearer in this section.
In the database terms, PostgreSQL uses a mode of the client / server. A PostgreSQL session consists of the following related processes (programs): a server process, which manages database files, accepted join from client applications and databases, and performs operations on the database on behalf of the client. The database server program is called Postmaster. Those clients (front ends) applications that need to perform database operations. Client application may be a variety of varieties: they can be a tool for a character interface, or a graphical interface application, or a web server that displays a web page by accessing the database, or a special database management tool . Some client applications are provided with PostgreSQL release, but most of them are developed by users. As with typical client / server applications (C / S applications), these clients and servers can be on different hosts. At this time they connect communication through TCP / IP networks. What you should remember is that the files that can be accessed on the client may not be able to access (or only access to different file names) on the database server machine. The PostgreSQL server can handle multiple concurrent requests from the client. Therefore, it starts for each request ("fork") a new process. From this time, the client and the new server process will no longer communicate with the initial Postmaster process. Therefore, Postmaster is always running, waiting for the coupling, the secondary client, and the associated server process to stop. (Of course, users are certainly not seeing these things. We talk about these mainly for complete.) 3, use the database
If you are interested, refer to the Chinese user manual, it's too long. If you have experience in using the database, you can quickly enter the PostgreSQL world. You can download the usage manual here.
If you still don't worry, look at the situation of the user below PostgreSQL.
4, postgreSQL user's situation
Affymetrix: (www.Affymetrix.com) A Biotechnology Research Company provides art-grade research tools for genetic research industries, in their Transcriptome project stores the massive RNA expression experiments generated from high-density genechip? Sequences in their Transcriptome project. AfiliaS: (www.nic.info) A domain name registration provider currently manages the first extension of the newly released on the Internet .info. It is a company located in Ireland and manages more than 900,000 domain names and more than 10 million records, which are stored in a database backend with PostgreSQL. BASF: (www.basf.com) This should be familiar with, BASFOR, the world's largest chemical company, using PostgreSQL to store data for their US agricultural integration e-commerce website. Cognitive: (http://www.cognitivity.com/) Online learning providers, use PostgreSQL for their performance software and management software. Journyx: (http://www.journyx.com) Worldly recognized Web-based service providers have more than one million end users. They use PostgreSQL for internal database operations on all of them (Linux, BSD, AIX, Solaris, and Macos X). Royal: Modern Royal Typewriter Company, and their online e-commerce website is stored in PostgreSQL. The American Chemical Society: American Chemical Community, www.acs.org, the world's largest professional chemistry, has more than 165,000 members, as well as a website that has more than 1,000 million people per day. Their publication archives store all publications (two million pages, more than 1T data), use PostgreSQL. (Currently known PostgreSQL's largest database). Tsutaya: Japan's largest video program lease chain, stores them more than a few g, millions of recorded data with PostgreSQL, and do their business information database. Oh, yes, there is Cisco, everyone to: http://www.cisco.com/public/pubsearch.html search PostgreSQL knows.
Reference:
Postgresql Chinese website http://laser.zhengmai.com.cn/
China Linux Forum http://www.linuxforum.net/
China UNIX Forum http://www.chinaunix.net
Develop PostgreSQL using C / C
Http://www-900.ibm.com/developerWorks/cn/linux/l-pgsql/index.shtml
