Rails 支持oracle 数据库

参考：（看第一个答案的时候，记得看我下面的注释）https://stackoverflow.com/questions/764887/how-to-configure-ruby-on-rails-with-oracle

1. 下载oracle相关的开发文件和sdk: 　来这里：https://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.html

这里要注意，选择　对应的平台和ＣＰＵ类型．例如，　for Linux-x86-64 就是当前主流cpu（６４位), 以及 Linux操作系统.

2. 进来之后,会看到这个页面, 记得要先选择"Accept" (在页面上方位置), 接受条款. 

然后点击" ...sdk " 和 "... basic" 两个zip文件.

（分别对应　Base ...   和　　Development and Runtime) 如下图所示：

下载时要记得注册Oracle账号. 否则无法下载.

3. 解压缩 zip 文件, 可以看到文件都解压缩到文件夹: instantclient_12_2  下了, 然后建立 soft link: 

(这句话很重要)     $ ln -s libclntsh.so.12.1 libclntsh.so   ( so 文件后缀是linux的, 如果在mac下,就是 dylib ) 

同时,在上面的页面, 要下载 xxx-sql-plus 文件. 也一样解压缩即可. 

上面3个文件解压缩之后, 文件都存在与 同一个文件夹下面,例如: 

/workspace/coding_tools/instantclient_12_2

drwxrwxr-x  3 siwei siwei      4096 5月  25 18:09 .
drwxrwxr-x 12 siwei siwei      4096 5月  25 18:09 ..
-rwxrwxr-x  1 siwei siwei     44220 1月  26 05:14 adrci
-rw-rw-r--  1 siwei siwei       363 1月  26 05:14 BASIC_README
-rwxrwxr-x  1 siwei siwei     57272 1月  26 05:14 genezi
-r-xr-xr-x  1 siwei siwei       342 1月  26 05:14 glogin.sql
-rwxrwxr-x  1 siwei siwei   8033199 1月  26 05:14 libclntshcore.so.12.1
lrwxrwxrwx  1 siwei siwei        17 5月  25 17:36 libclntsh.so -> libclntsh.so.12.1
-rwxrwxr-x  1 siwei siwei  71638263 1月  26 05:14 libclntsh.so.12.1
-r-xr-xr-x  1 siwei siwei   2981501 1月  26 05:14 libipc1.so
-r-xr-xr-x  1 siwei siwei    539065 1月  26 05:14 libmql1.so
-r-xr-xr-x  1 siwei siwei   6568149 1月  26 05:14 libnnz12.so
-rwxrwxr-x  1 siwei siwei   2218687 1月  26 05:14 libocci.so.12.1
-rwxrwxr-x  1 siwei siwei 124771800 1月  26 05:14 libociei.so
-r-xr-xr-x  1 siwei siwei    158543 1月  26 05:14 libocijdbc12.so
-r-xr-xr-x  1 siwei siwei    380996 1月  26 05:14 libons.so
-rwxrwxr-x  1 siwei siwei    116563 1月  26 05:14 liboramysql12.so
-r-xr-xr-x  1 siwei siwei   1641005 1月  26 05:14 libsqlplusic.so
-r-xr-xr-x  1 siwei siwei   1559466 1月  26 05:14 libsqlplus.so
-r--r--r--  1 siwei siwei   4036257 1月  26 05:14 ojdbc8.jar
drwxrwxr-x  5 siwei siwei      4096 1月  26 05:14 sdk
-r-xr-xr-x  1 siwei siwei     22751 1月  26 05:14 sqlplus
-rw-rw-r--  1 siwei siwei       367 1月  26 05:14 SQLPLUS_README
-rwxrwxr-x  1 siwei siwei    240476 1月  26 05:14 uidrvci
-rw-rw-r--  1 siwei siwei     74230 1月  26 05:14 xstreams.jar

设置  变量: export LD_LIBRARY_PATH=/workspace/coding_tools/instantclient_12_2

放到 ~/.bashrc 文件中, 重新进入terminal 

4. 开始安装oci8  , 参考:   http://www.rubydoc.info/github/kubo/ruby-oci8/file/docs/install-instant-client.md

$ gem install ruby-oci8

5. 安装 相关的Gem: 

I was using rails 4.1.x, Gemfile:

gem 'activerecord-oracle_enhanced-adapter', '~> 1.5.0'   (这个版本,需要根据Rails的来调整,见官方文档)
gem 'ruby-oci8', '2.2.3'

6. 修改database.yml: 

default: &default
  adapter: oracle_enhanced
  username: SYlala
  password: SYlala

  # 写法1:
  database: 218.5.22.22/your_db
  # 写法2:  database:  oracle的tns字符串
  database: "(DESCRIPTION=
    (ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=218.5.22.22)(PORT=1521)))
    (CONNECT_DATA=(SERVICE_NAME=your_db))
    )"

development:
  <<: *default

7. 设置一个model:  (https://github.com/rsim/oracle-enhanced)

class User < ActiveRecord::Base
    self.table_name ='tuser'   # 设置表名字,具体还有很多设置方法, 见oracle-hanced的官方wiki
end

8. 开始测试

$ bundle install

$ bundle exec rails console

rails >  User.first 

irb(main):001:0> User.first
  Sequence (94.0ms)  select us.sequence_name from all_sequences us where us.sequence_owner = 'SYCORP' and us.sequence_name = 'TUSER_SEQ'
  Primary Key (130.0ms)  SELECT cc.column_name FROM all_constraints c, all_cons_columns cc WHERE c.owner = 'SYCORP' AND c.table_name = 'TUSER' AND c.constraint_type = 'P' AND cc.owner = c.owner AND cc.constraint_name = c.constraint_name
  User Load (474.8ms)  SELECT * FROM (SELECT  "TUSER".* FROM "TUSER"   ORDER BY "TUSER"."ID" ASC) WHERE ROWNUM <= 1
   (1876.2ms)  SELECT column_name AS name, data_type AS sql_type, data_default, nullable, virtual_column, hidden_column, data_type_owner AS sql_type_owner, DECODE(data_type, 'NUMBER', data_precision, 'FLOAT', data_precision, 'VARCHAR2', DECODE(char_used, 'C', char_length, data_length), 'RAW', DECODE(char_used, 'C', char_length, data_length), 'CHAR', DECODE(char_used, 'C', char_length, data_length), NULL) AS limit, DECODE(data_type, 'NUMBER', data_scale, NULL) AS scale FROM all_tab_cols WHERE owner = 'SYCORP' AND table_name = 'TUSER' AND hidden_column = 'NO' ORDER BY column_id
=> #<User id: 0, userid: "admin", password: "3a55dd3d48ef45fea12dc8854776313c", name: "???", grade: 0, lastlogin: "2017-05-27 16:34:13", logins: 12954, chgpwdtime: "2017-04-17 11:58:29", chgpwdlimit: 10000, status: 1, iplimit: nil, certno: nil, orgid: 3, photo: "\v\xC1\xBF\xB7\xBF\xCD\xBC2.jpg\xFF\xD8\xFF\xE0\x00\x10JFIF\x00\x01\x02\x00\x00\x01\x00\x01\x00\x00\xFF\xDB\x00C\x00\b\x06\x06\a\x06\x05\b\a\a\a\t\t\b...", femployee: 98, email: nil, flogins: #, fphone: nil, userattribute: nil>

9. 最后,如果是中文的话,记得设置 数据库的编码格式.

在config/boot.rb中, 加入: ENV['NLS_LANG'] ||= 'AMERICAN_AMERICA.UTF8'