postgresql 创建一个新的database system
第一步：su postgres
第二步：bash-4.2$ /usr/(pgsql-9.1)/bin/initdb -D /var/lib/pgsql/9.1/data/ ， 回车后出现如下信息 (红色表示可能没有这个目录)
The files belonging to this database system will be owned by user "postgres".This user must also own the server process.
The database cluster will be initialized with locale en_US.UTF-8.
The default database encoding has accordingly been set to UTF8.
The default text search configuration will be set to "english".
fixing permissions on existing directory /var/lib/pgsql/9.1/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 24MB
creating configuration files ... ok
creating template1 database in /var/lib/pgsql/9.1/data/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating collations ... ok
creating conversions ... ok
creating dictionaries ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
loading PL/pgSQL server-side language ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok
WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the -A option the
next time you run initdb.
Success. You can now start the database server using:
/usr/pgsql-9.1/bin/postgres -D /var/lib/pgsql/9.1/data
or
/usr/pgsql-9.1/bin/pg_ctl -D /var/lib/pgsql/9.1/data -l logfile start
第三步：用上边两个命令中的一个启动服务
第四步：创建一个用户（user）
bash-4.2$ createuser qiaoning -P
Enter password for new role: //输入密码
Enter it again: //再次输入密码
Shall the new role be a superuser? (y/n) n //是否是超级用户，选否
Shall the new role be allowed to create databases? (y/n) y //该用户是否可以创建数据库，选是
Shall the new role be allowed to create more new roles? (y/n) n //该用户是否可以创建新的角色，选否
第五步：创建数据库
bash-4.2$ createdb qiaoning --owner=qiaoning //第一个qiaoning是数据库名称，第二个qiaoning是数据库的拥有者
以上步骤完成后需要修改一些配置文件（主要是访问权限的设置）
第一步：进入刚才创建的database system所在的目录，即：/var/lib/pgsql/9.1/data/
第二步：修改pg_dba.conf，如下
# PostgreSQL Client Authentication Configuration File
# ===================================================
#
# Refer to the "Client Authentication" section in the PostgreSQL
# documentation for a complete description of this file. A short
# synopsis follows.
#
# This file controls: which hosts are allowed to connect, how clients
# are authenticated, which PostgreSQL user names they can use, which
# databases they can access. Records take one of these forms:
#
# local DATABASE USER METHOD [OPTIONS]
# host DATABASE USER ADDRESS METHOD [OPTIONS]
# hostssl DATABASE USER ADDRESS METHOD [OPTIONS]
# hostnossl DATABASE USER ADDRESS METHOD [OPTIONS]
#
# (The uppercase items must be replaced by actual values.)
#
# The first field is the connection type: "local" is a Unix-domain
# socket, "host" is either a plain or SSL-encrypted TCP/IP socket,
# "hostssl" is an SSL-encrypted TCP/IP socket, and "hostnossl" is a
# plain TCP/IP socket.
#
# DATABASE can be "all", "sameuser", "samerole", "replication", a
# database name, or a comma-separated list thereof. The "all"
# keyword does not match "replication". Access to replication
# must be enabled in a separate record (see example below).
#
# USER can be "all", a user name, a group name prefixed with "+", or a
# comma-separated list thereof. In both the DATABASE and USER fields
# you can also write a file name prefixed with "@" to include names
# from a separate file.
#
# ADDRESS specifies the set of hosts the record matches. It can be a
# host name, or it is made up of an IP address and a CIDR mask that is
# an integer (between 0 and 32 (IPv4) or 128 (IPv6) inclusive) that
# specifies the number of significant bits in the mask. A host name
# that starts with a dot (.) matches a suffix of the actual host name.
# Alternatively, you can write an IP address and netmask in separate
# columns to specify the set of hosts. Instead of a CIDR-address, you
# can write "samehost" to match any of the server's own IP addresses,
# or "samenet" to match any address in any subnet that the server is
# directly connected to.
#
# METHOD can be "trust", "reject", "md5", "password", "gss", "sspi",
# "krb5", "ident", "peer", "pam", "ldap", "radius" or "cert". Note that
# "password" sends passwords in clear text; "md5" is preferred since
# it sends encrypted passwords.
#
# OPTIONS are a set of options for the authentication in the format
# NAME=VALUE. The available options depend on the different
# authentication methods -- refer to the "Client Authentication"
# section in the documentation for a list of which options are
# available for which authentication methods.
#
# Database and user names containing spaces, commas, quotes and other
# special characters must be quoted. Quoting one of the keywords
# "all", "sameuser", "samerole" or "replication" makes the name lose
# its special character, and just match a database or username with
# that name.
#
# This file is read on server startup and when the postmaster receives
# a SIGHUP signal. If you edit the file on a running system, you have
# to SIGHUP the postmaster for the changes to take effect. You can
# use "pg_ctl reload" to do that.
# Put your actual configuration here
# ----------------------------------
#
# If you want to allow non-local connections, you need to add more
# "host" records. In that case you will also need to make PostgreSQL
# listen on a non-local interface via the listen_addresses
# configuration parameter, or via the -i or -h command line switches.
# CAUTION: Configuring the system for local "trust" authentication
# allows any local user to connect as any PostgreSQL user, including
# the database superuser. If you do not trust all your local users,
# use another authentication method.
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all trust
# IPv4 local connections:
host all all 127.0.0.1/32 trust
host all all 192.168.2.0/24 trust #这儿是新加的
# IPv6 local connections:
host all all ::1/128 trust
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local replication postgres trust
#host replication postgres 127.0.0.1/32 trust
#host replication postgres ::1/128 trust
第三步：修改postgresql.conf，如下（只摘录了一部分）
#------------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#------------------------------------------------------------------------------
# - Connection Settings -
listen_addresses = '*'#*这儿以前是localhost# what IP address(es) to listen on;
# comma-separated list of addresses;
# defaults to 'localhost', '*' = all
# (change requires restart)
#port = 5432 # (change requires restart)
max_connections = 100 # (change requires restart)
好了，大功告成，接下来就连接数据库吧，就一句话：
[root@localhost data]# psql -U qiaoning -d qiaoning -h 192.168.2.118 //第一个qiaoning是user，第二个是database，回车后出现如下信息
psql (9.1.2)
Type "help" for help.
qiaoning=>