CentOS Rails 環境安裝

安裝 Apache & PostgreSQL

$ service --status-all # 檢查服務運行的狀態
$ yum list installed # 檢查已安裝的 yum packages
$ yum install httpd # 安裝 apache
$ yum install postgresql postgresql-server postgresql-devel postgresql-libs # 安裝 PostgreSQL，注意沒裝 devel 和 libs 裝 gem 時會出錯。

# 第一次啟動如果炸掉 ERROR:  `/var/lib/pgsql/data is missing. Use “service postgresql initdb” to initialize the cluster first.`
$ service postgresql initdb

# 如果又遇到 Initializing database: mkdir: cannot create directory `/var/lib/pgsql/data/pg_log': File exists
$ rm -rf /var/lib/pgsql/data/pg_log # 把 log 刪除

$ service postgresql start # 啟動 PostgreSQL
$ chkconfig postgresql on # 設定開機後自動啟動

# 修改 /var/lib/pgsql/data/pg_hba.conf (預設路徑)
# local all all ident sameuser
local all all trust
# host all all 127.0.0.1/32 ident sameuser
host all all 127.0.0.1/32 md5

# 註：md5 和 trust 差別在於 trust 允許在本機不用輸入密碼來登入資料庫。

# 由於變更設定檔需要 reload
$ su - postgres
$ pg_ctl reload
$ psql # 進入介面開 table 或建立 users 權限

# 列出 database
$ \list
$ \l

# 連線該 db
$ \connect [database_name]

# 重設密碼
$ \password

# 在 command line 裡分成兩種方式一種是先切換成 postgres 使用者身份直接下指令，另一種是登入 psql 後下 sql 指令
# 預設 PostgreSQL 只允許本機上的 user 和 PostgreSQL 中 role name 相同的帳號不用密碼登入
# 預設只有 db 的 owner 可以操作裡面的東西(不包含 superuser)

# 建立 db role
$ createuser test_user # 這種方式會有精靈讓你選權限

# SQL下指令記得加 ;
# 建立 db role (SQL)
$ create role [rails_user] with createdb login password 'password here';

# 修改 role (SQL)
$ alter role [rails_user] with createdb login password 'password here';

# 列出所有使用者的權限
$ \du

# 顯示所有 roles 名稱(SQL)
$ select rolname from pg_roles;

# 查看 table 權限
$ \z

# 列出所有 table
$ \dt

# 當前的使用者
$ select current_user;

# 當前連線的 db
$ select current_database();

# 離開 psql
$ \q

# 檢查 PostgreSQL status
$ service postgresql status

# 移除 db (OSX)
$ rm /usr/local/var/postgres/postmaster.pid
$ dropdb rbase_test

# 在 SQL 中移除 db
$ drop database if exists [database name]

# 列出 tables
$ \dt

# 建立新資料庫
$ CREATE DATABASE mydb;

# 建立使用者
$ CREATE USER andy with password 'p@ssw0rd';
$ createuser test --interactive -P # 含建立密碼 + 權限

# 連線資料庫
$ \c database

# 建立 table 範例
CREATE TABLE films (
  code        char(5) CONSTRAINT firstkey PRIMARY KEY,
  title       varchar(40) NOT NULL,
  did integer NOT NULL,
  date_prod   date,
  kind        varchar(10),
  len         interval hour to minute
);

# 列出 table schema
$ \d+ [tablename]

# 刪除 table
DROP TABLE IF EXISTS table;

# 插入資料
INSERT INTO films VALUES
('UA502', 'Bananas', 105, DEFAULT, 'Comedy', '82 minutes');

INSERT INTO films (code, title, did, date_prod, kind)
VALUES ('T_601', 'Yojimbo', 106, DEFAULT, 'Drama'),
('HG120', 'The Dinner Game', 140, DEFAULT, 'Comedy');


# 選取 table 大小和隨機的指數
SELECT relname, reltuples, relpages FROM pg_class ;

# select size of tables and indices in descending order of size
SELECT relname, reltuples, relpages FROM pg_class ORDER BY relpages DESC ;

# select size of tables and indices in descending order of tuple- / recordcount
SELECT relname, reltuples, relpages FROM pg_class ORDER BY reltuples DESC ;

# 修改密碼
$ su - postgres
$ psql template1
$ alter user postgres with password 'postgres_password';

# 列出使用者
SELECT * FROM "pg_user";

# change user for all tables
for tbl in `psql -qAt -c "select tablename from pg_tables where schemaname = 'public';" YOUR_DB` ; do psql -c "alter table $tbl owner to NEW_OWNER" YOUR_DB ; done

# change user for all seqs
for tbl in `psql -qAt -c "select sequence_name from information_schema.sequences where sequence_schema = 'public';" YOUR_DB` ; do psql -c "alter table $tbl owner to NEW_OWNER" YOUR_DB ; done

# change user for all views
for tbl in `psql -qAt -c "select table_name from information_schema.views where table_schema = 'public';" YOUR_DB` ; do psql -c "alter table $tbl owner to NEW_OWNER" YOUR_DB ; done

# 複製資料庫
create database NEWDB with template OLDDB;

# 修改 DB owner/name
ALTER DATABASE name RENAME TO newname
ALTER DATABASE name OWNER TO new_owner

# Showing transaction status in the psql prompt
$ \set PROMPT1 '%/%R%x%# '
# from http://sql-info.de/postgresql/notes/transaction-status-in-the-psql-prompt.html

# 列出資料表欄位

SELECT attname FROM pg_attribute, pg_type
WHERE typname = 'table_name'
AND attrelid = typrelid
AND attname NOT IN ('cmin', 'cmax', 'ctid', 'oid', 'tableoid', 'xmin', 'xmax');

# 備份 / 還原 使用 Dump
# 備份
$ pg_dump dbname > outfile
$ pg_dump dbname | gzip > filename.gz

# 還原
$ psql dbname < infile
$ createdb dbname && gunzip -c filename.gz | psql dbname

# 更新
$ update auth_user set is_superuser = 't' where username='abhiomkar';

```
[完整 PostgreSQL 建立 ROLE 教學](https://www.digitalocean.com/community/tutorials/how-to-use-roles-and-manage-grant-permissions-in-postgresql-on-a-vps--2)
[OSX PostgreSQL Installing](https://marcinkubala.wordpress.com/2013/11/11/postgresql-on-os-x-mavericks/)
[OSX 簡易控制 PostgreSQL](http://robots.thoughtbot.com/starting-and-stopping-background-services-with-homebrew)

## 安裝 Rails

```
# 1. 安裝 git
$ yum install curl-devel expat-devel gettext-devel \
  openssl-devel zlib-devel

# 取得原始碼 https://www.kernel.org/pub/software/scm/git/
$ wget https://www.kernel.org/pub/software/scm/git/git-2.2.0.tar.gz
$ tar -zxf git-2.0.0.tar.gz
$ make prefix=/usr/local all  # 注意換路徑不需要加到 bin
$ sudo make prefix=/usr/local install

? Ruby with Readline 尚未測試成功

# 2. 安裝 Ruby
$ yum install -y gcc openssl-devel libyaml-devel libffi-devel readline-devel zlib-devel gdbm-devel ncurses-devel
$ wget http://cache.ruby-lang.org/pub/ruby/2.2/ruby-2.2.0.tar.gz
$ tar -zxvf ruby-2.0.0.tar.gz
$ ./configure
$ make && make install
$ gem install bundler


# 安裝 Rails 之前先安裝 sqlite3
$ yum install sqlite-devel
$ yum install readline-devel
$ gem install rails

$ cd [YOUR_PROJECT]
$ bundle install

常見問題
日文完整教學