BlogJava-探索与发现-随笔分类-ruby

rails find method

蜘蛛 — Sat, 31 Mar 2007 08:17:00 GMT

a=Movie.find(1)
a=Movie.find_by_name("g")
a=Comment.find(:all,:conditions=>"comment like '%thi%'")

蜘蛛 2007-03-31 16:17 发表评论

rails 表与表关系

蜘蛛 — Sat, 31 Mar 2007 08:08:00 GMT

ruby里的表对应的三关系:
在mysql里创建两张表
mysql> create table invoices(
    -> id int primary key auto_increment,
    -> order_id int,
    -> created_at timestamp
    -> );
Query OK, 0 rows affected (0.28 sec)

mysql> create table orders(
    -> id int primary key auto_increment,
    -> company varchar(30)
    -> );
Query OK, 0 rows affected (0.23 sec)
(1)one to one relationShip:
   order.rb
   class Order < ActiveRecord::Base
   has_one:invoice
   end

   invoice.rb
   class Invoice < ActiveRecord::Base
    belongs_to:order
   end

   D:\ruby\mytest\mytest1>ruby script\console
   Loading development environment.
   >> order=Order.new
   => #nil}>
   >> order.company="Big Corp"
   => "Big Corp"
   >> order.save
   => true

   >> invoice=Invoice.new
   => #nil, "created_
   at"=>nil}>
   >> order.invoice=invoice
   => #   e=#>, @new_record=false, @attributes={"order_id"=>1, "id"
   =>1, "created_at"=>Sat Mar 31 14:41:32 +0800 2007}>
   >>

(2)one to many
mysql> create table comments
    -> (
    -> id int primary key auto_increment,
    -> comment varchar(5000),
    -> created_at timestamp,
    -> updated_at timestamp
    -> );
Query OK, 0 rows affected (0.31 sec)

mysql> alter table comments add critic_id int;
Query OK, 0 rows affected (0.42 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> create table critics
    -> (
    -> id int primary key auto_increment,
    -> firstname varchar(30),
    -> lastname varchar(30),
    -> email varchar(30)
    -> );
Query OK, 0 rows affected (0.11 sec)

class Critic < ActiveRecord::Base
has_many:comment
end

class Comment < ActiveRecord::Base
belongs_to:critic
end

D:\ruby\mytest\mytest1>ruby script\console
Loading development environment.
>> a_critic=Critic.new
=> #nil, "firstname
"=>nil, "email"=>nil}>
>> a_critic.lastname="adm"
=> "adm"
>> a_critic.save
=> true
>> a_comment=Comment.new
=> #nil, "critic
_id"=>nil, "comment"=>nil, "created_at"=>nil}>
>> a_comment.comment="this is a movie"
=> "this is a movie"
>> a_critic.comment<

(3)many to many
   有三张表table1s ,table1s_table2s,table2s
   分别在table1.rb,table2.rb增加下面的语句
   has_and_belongs_to_many:table1;
   has_and_belongs_to_many:table2
操作与(2)相似

蜘蛛 2007-03-31 16:08 发表评论

使用scoffold小记

蜘蛛 — Sat, 24 Mar 2007 10:40:00 GMT

只适用于window平台:
假设之前你已经装好了ruby,rails,mysql
1) 启动mysql
    d:\>net start mysql
2) 优化mysql
    d:\>gem install mysql
这会提示出很多版本,确保你选择的是高版本而且是以(mswin32)结尾的产品
3) 创建rails项目
    d:\>rails cookbook
    进入cookbook目录
    这样子默认使用的是mysql数据库,如果想使用PostgreSQL,
    就要这样子指定它创建项目了d:>rails cookbook --database=postgresql
    d:\>cd cookbook
4) 数据库test创建表languages,我的数据库的用户名是root,密码是root
    我们使用rails创建表
    1:打开cookbook\config\database.yml修改为

    development:
adapter: mysql
database: test
username: root
password: root
host: localhost

# Warning: The database defined as 'test' will be erased and
# re-generated from your development database when you run 'rake'.
# Do not set this db to the same as development or production.
test:
adapter: mysql
database: cookbook_test
username: root
password: root
host: localhost

production:
adapter: mysql
database: cookbook_production
username: root
password: root
host: localhost
2:创建一个migration脚本
d:\cookbokk>ruby script/generate migration build_db
打开db/migrate/001_build_db.rb
修改如下:

class BuildDb < ActiveRecord::Migration
def self.up
    create_table :languages,:force=>true do |t|
                      t.column :name,:string
                      t.column :description,:string
    end
end

def self.down
    drop_table :languages
end
end

3:执行d:\cookbook> rake db:migrate
这时你的数据库表应该创建了

5)有两种方式创建scaffolding
<第一种方式>
1)ruby script/generate model language
2)ruby script/generate controller language
3)修改这个文件为如下内容app/controllers/language_controller.rb:

    class LanguageController < ApplicationController
    scaffold :languages
    end
										
												

										
								
4)启动服务器ruby script/server
5)访问http://localhost:3000/languages

<第二种方式>
1)ruby script/generate scaffold language
2) 启动服务器ruby script/server
3)访问http://localhost:3000/languages

蜘蛛 2007-03-24 18:40 发表评论