Difference between revisions of "PostgreSQL (简体中文)"

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PostgreSQL是一个开源的,社区驱动的,符合标准的 对象-关系型 数据库系统。
 
本文档介绍如何安装PostgreSql,以及如何与[[PHP]] 和 [[Apache]]进行交互。同时,也介绍了如何配置PostgreSql,以使得远程服务端能够操作之。此处默认[[PHP]]和[[Apache]] 已经安装并配置完毕,如果您恰好没有安装此两个软件,请参考[[LAMP]]。
 
本文档介绍如何安装PostgreSql,以及如何与[[PHP]] 和 [[Apache]]进行交互。同时,也介绍了如何配置PostgreSql,以使得远程服务端能够操作之。此处默认[[PHP]]和[[Apache]] 已经安装并配置完毕,如果您恰好没有安装此两个软件,请参考[[LAMP]]。
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 +
==开始之前==
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有些地方会有“成为postgres用户”的指示。如果已经安装udo,请执行以下操作,以postgres用户获得一个shell:
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sudo -i -u postgres
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否则,使用su命令:
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su root
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su - postgres
 +
  
 
==安装PostgreSQL==
 
==安装PostgreSQL==

Revision as of 13:33, 2 April 2013

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PostgreSQL是一个开源的,社区驱动的,符合标准的 对象-关系型 数据库系统。 本文档介绍如何安装PostgreSql,以及如何与PHPApache进行交互。同时,也介绍了如何配置PostgreSql,以使得远程服务端能够操作之。此处默认PHPApache 已经安装并配置完毕,如果您恰好没有安装此两个软件,请参考LAMP

开始之前

有些地方会有“成为postgres用户”的指示。如果已经安装udo,请执行以下操作,以postgres用户获得一个shell:

sudo -i -u postgres

否则,使用su命令:

su root
su - postgres


安装PostgreSQL

  • 安装postgresql
$ sudo pacman -S postgresql
  • 启动PostgreSQL服务器 (第一次启动,将创建一个数据目录和需要使用此服务器的用户列表,此时,会看到大量的输出文字。)
$ sudo /etc/rc.d/postgresql start
  • 确认postgres用户创立成功,并且把该用户加入所属组postgres中。
$ groups postgres
  • (可选)把postgresql加入/etc/rc.conf中的daemons列表里,使系统启动时,postgresql作为守护进程同时启动。

创建第一个数据库

  • 成为postgres用户(此用户在执行"/etc/rc.d/postgres start"时已经被创建)
su root
su - postgres
  • 新增数据库用户:
createuser -DRSP <username>

-D 此用户不能创建数据库
-R 此用户不能创建角色
-S 此用户不能成为超级用户
-P Prompt for password will be issued

或者更灵活的,可以不输入任何参数来创建新用户,通过回答一些系统问题来确定用户角色:

# createuser <username>
Shall the new role be a superuser? (y/n)  n
Shall the new role be allowed to create databases? (y/n)  y
Shall the new role be allowed to create more new roles? (y/n)  y

If you create a user as per your login user ($USER) it allows you to access the postgresql database shell without having to specify a user to login as (which makes it quite convenient).

  • 以具备读写权限的用户身份,创建一个新的数据库
createdb -O username databasename [-E database_encoding]
  • 就这样,您的第一个数据库被创建成功。

熟悉PostgreSQL

Access the database shell

  • Become the postgres user the first time, so we can assign permissions to you (your primary user)
$ sudo su postgres
  • Start the primary db shell, where you can do all your creation of databases/tables, deletion, set permissions, and run raw SQL commands.
$ psql
--You can optionally use `psql <database_name>` to administer an individual database.
  • 连接一个特定的数据库
=> \c <database>
  • 列出所有的用户和他们的相关权限级别
=> \du
  • 显示当前数据库的总况
=> \dt

There are of course many more meta-commands, but these should help you get started.

Configure PostgreSQL to be accessible from remote

The PostgreSQL database server configuration file is postgresql.conf. This file is located in the data directory of the server, typically /var/lib/postgres/data. This folder also houses the other main config files, including the pg_hba.conf.

Note: By default this folder will not even be browseable (or searchable) by a regular user, if you are wondering why `find` or `locate` isn't finding the conf files, this is the reason (threw me for a loop the first time I installed).
  1. As root user edit the file
    $ sudo vim /var/lib/postgres/data/postgresql.conf
  2. In the connections and authentications section uncomment or edit the listen_addresses line to your needs
    listen_addresses = '*'
    and take a careful look at the other lines.
  3. Hereafter insert the following line in the host-based authentication file /var/lib/postgres/data/pg_hba.conf. This file controls which hosts are allowed to connect, so be careful.
    # IPv4 local connections: <br>host   all   all   your_desired_ip_address/32   trust
    whereas your_desired_ip_address is the ip address of the client.
  4. After this you should restart the daemon process for the changes to take effect with
    $ sudo /etc/rc.d/postgresql restart
Note: Postgresql uses port 5432 by default for remote connections. So make sure this port is open and able to receive incoming connections

For troubleshooting take a look in the server log file

tail /var/log/postgresql.log

Configure PostgreSQL to Work With PHP

  1. Install the PHP-PostgreSQL modules
    $ pacman -S php-pgsql 
  2. Open the file /etc/php/php.ini with your editor of choice, e.g.,
    # vim /etc/php/php.ini
  3. Find the line that starts with, ";extension=pgsql.so" and change it to, "extension=pgsql.so". (Just remove the preceding ";"). If you need PDO, do the same thing with ";extension=pdo.so" and ";extension=pdo_pgsql.so". If this lines are not present, add it. This lines may be in the "Dynamic Extensions" section of the file, or toward the very end of the file.
  4. Restart the Apache web server
    # /etc/rc.d/httpd restart

Installing phpPgAdmin (optional)

phpPgAdmin is a web-based administration tool for PostgreSQL. It can be installed two ways.

Option A: install via Pacman (preferred)

  1. Make sure that the [community] repo is enabled.
  2. Install the package via Pacman
    # pacman -S phppgadmin

Option B: install via a manual install (the old way)

  1. Download the latest .bz2 file from here into the root of your server directory
    wget -P /home/httpd/html http://downloads.sourceforge.net/phppgadmin/phpPgAdmin-4.1.3.tar.bz2
  2. Extract the file into the new directory
    tar -C /home/httpd/html/ -jxvf /home/httpd/html/phpPgAdmin-4.1.3.tar.bz2
  3. Remove the tar file
    rm /home/httpd/html/phpPgAdmin-4.1.3.tar.bz2
  4. Change the name of the directory created in the previous step to include the version number (this will help in the future when upgrading)
    mv /home/httpd/html/phpPgAdmin /home/httpd/html/phpPgAdmin-4.1.3/
  5. Create a link to that directory (for ease of linking and upgrading)
    ln -s /home/httpd/html/phpPgAdmin-4.1.3/ /home/httpd/html/phpPgAdmin
  6. Copy the included generic config file
    cp /home/httpd/html/phpPgAdmin/conf/config.inc.php-dist /home/httpd/html/phpPgAdmin/conf/config.inc.php


The config file is located at /home/httpd/html/phpPgAdmin/conf/config.inc.php. No changes should be required. Check this page for any other setup questions that you might have.

Postgresql升级配置

Warning: Official postgresql upgrade documentation should be followed.

首先要明确:这个说明可能导致数据丢失,因此,后果自负.即使这个在我这边没问题,也不代表其他所有的服务器都会没问题。

最好是在/etc/pacman.conf里加上下面这行:

IgnorePkg = postgresql

This will make sure that you don't accidentally upgrade the database to an incompatible version. If you did an accidental upgrade you might not be able to access any of your data. Always check the Postgresql home page (http://www.postgresql.org/) to be sure of what steps are required for each upgrade. For a bit about why this is the case see this.

How to dump all of your data, upgrade PostgreSQL, and then restore all of your data (this may not be necessary for every upgrade, see #2 above)

Become the root user

su

Become the postgres user

su postgres

Change the current directory to one that the postgres user can write to

eg. cd ~/data/

Dump the current contents of the database

pg_dumpall > pgs_db.out

Unless you have a .pgpass file setup, you will be required to enter your password a few times (the number of times is roughly equal to the number of databases that you have + 2). One problem occurs if you don't have a password defined for the postgres user but you require local users to authenticate. In this case you will be asked to give a password that doesn't exist. To work around this problem, add a line to your pg_hba.conf file to trust the postgres user. You can remove this line after the upgrade is complete. So, the first line of the 'local' section of pg_hba.conf would look something like this:

local     all postgres                                trust

Log out of the postgres user and return to superuser

exit

停止PostgreSQL服务器

/etc/rc.d/postgresql stop

移走Postgresql数据目录

mv /var/lib/postgres /var/lib/postgres_old

升级postgresql

pacman -S postgresql

启动PostgreSQL服务器

/etc/rc.d/postgresql start

切换为postgres用户

su postgres

Change the current directory to the directory that you dumped the data out to (in step 4 above)

eg. cd /var/lib/postgres_old/data/

Restore the database

psql -e template1 -f pgs_db.out

More Resources