Ruby on Rails

MYSQL DATAT TYPES EXPLANATION? What is data type 1. A data type specifies a particular type of data, such as integer, floating-point, Boolean etc. 2. A data type also specifies the possible values for that type, the operations that can be performed on that type and the way the values of that type are stored. MySQL data types MySQL supports a number of SQL standard data types in various categories. MySQL has Numeric Types, the DATETIME, DATE, and TIMESTAMP Types and String Types. Data types are discussed on this page are based on MySQL community server 5.6 MySQL Numeric Types MySQL supports all standard SQL numeric data types which include INTEGER, SMALLINT, DECIMAL, and NUMERIC. It also supports the approximate numeric data types (FLOAT, REAL, and DOUBLE PRECISION). The keyword INT is a synonym for INTEGER, and the keywords DEC and FIXED are synonyms for DECIMAL. DOUBLE is a synonym for DOUBLE PRECISION (a nonstandard extension). REAL is a synonym for DOUBLE PRECISION (a nonstandar...

Paperclip uploading files (or)images to amazon s3 for Ruby on rails ? 1)Add a gem 'gem 'aws-sdk' 2)bundle install 3)app/models/profile.rb-----Model add this code has_attached_file :image,                    :storage => :s3,                    :bucket => "yyyyyy",                    :s3_permissions => "public-read",                    :path => "profiles/:id/:basename.:extension",                    :s3_credentials => {                 ...

rake db:rollback in rails ? General-> rake db:migrate ->This will migrate your database by running migrations that are not run yet Running ->specific Migration     ->rake db:migrate VERSION=20130717110623 ->    This runs specific migration file from your db/migrate directory having version 20130717110623 Running up from migration->     rake db:migrate:up VERSION=20130717110623 ->    This runs up part from your migration Running down from migration ->    rake db:migrate:down VERSION=20130717110623     ->This runs down part from your migration Re-Running Specific Migration ->    rake db:migrate:redo VERSION=20130717110623 ->    This will first run down part and then up part of the migration having version 20130717110623 Re-Running all migrations     ->rake db:migrate:redo ->    This will re-run all t...

Can you get DB username, pw, database name in Rails? Rails.configuration.database_configuration[Rails.env] => {"encoding"=>"unicode", "username"=>"postgres", "adapter"=>"postgresql", "port"=>5432, "host"=>"localhost", "password"=>"postgres", "database"=>"mydb", "pool"=>5} (or) config   = Rails.configuration.database_configuration host     = config[Rails.env]["host"] database = config[Rails.env]["database"] username = config[Rails.env]["username"] password = config[Rails.env]["password"] (or) con = Mysql.real_connect("host", "user", "pw", "current_db") (or) Rails.configuration.database_configuration["development"]["database"]   

Create migration files in rails from existing mysql table? Start by referencing your existing MySQL database in database.yml run rake db:schema:dump to generate the schema.rb file Paste the create_table methods from your schema.rb into a new migration, and Voila! ##generate schema.rb ruby script/generate migration Tabledata migration file inside add the schema.rb remove this line 1)ActiveRecord::Schema.define(:version => 0) do end 2)rake db:migrate    

Get user accessing ip address rails? request.ip ->returns the ip, whether is is a local proxy ip (localhost address) or not. *request.remote_ip -> is smarter and gets the ip address of the client outside of local proxies. 3)If you are using apache in front of a mongrel, then remote_ip will return the source address of the request, which in this case will be local host because the Apache web server is making the request, so instead put this in your controller: @remote_ip = request.env["HTTP_X_FORWARDED_FOR"]

How to programmatically list all controllers in Rails? ApplicationController.subclasses.each do |c|   puts "Controller: #{c}"   puts "Actions: #{c.constantize.action_methods.collect{|a| a.to_s}.join(', ')}" end

Mysql Queries ? 1)createing table in mysql create table users(id int not null primary key,name char(25),address varchar(100),dob date); (or) CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255), PRIMARY KEY (P_Id) ) 2)inserting data to tables; insert into  users(id,name,address,dob) values(1,"sanjeevreddy","kachiguda",STR_TO_DATE('1-01-2012', '%d-%m-%Y')) 3)Add coloumn to mysql table alter table users add column last_name varchar(255) not null ,add column  email varchar(240); 4)deleting table drop table profiless; drop table table_name; 5)updating table data  update users set name ="reddy" where id = 1; 6)total databases show databases; 7)show table attributes desc table_name; desc users; ===================================== Database A database consists of one or more tables. A table is identified by its name. A ta...

Rails4 routes ? When a Rails application boots then it reads the config/routes.rb file. In your routes you might have code like this Rails4demo::Application.routes.draw do   root 'users#index'   resources :users   get 'photos/:id' => 'photos#show', :defaults => { :format => 'jpg' }   get '/logout' => 'sessions#destroy', :as => :logout   get "/stories" => redirect("/photos") end In the above case there are five different routing statements. Rails needs to store all those routes in a manner such that later when url is '/photos/5' then it should be able to find the right route statement that should handle the request. In this article we are going to take a peek at how Rails handles the whole routing business. Normalization in action In order to compare various routing statements first all the routing statements need to be normalized to a standard format so that one can easily co...

rails_best_practices gem Usage in rails ? 1)add in Gemfile gem "rails_best_practices" 2)bundle install 3)bundle exec rails_best_practices 4)rails_best_practices -d Useful link

How to Deploy a Rails 4 App With Git and Capistrano Setup your local Rails app to deploy to your production server using Capistrano and Git so your deployment process is automated, fast, and your brain hurts less. ? I think the two key aspects of any deployment process are speed and consistency. Speed means you can iterate and fix bugs fast and keep your production code in sync with your development code. Consistency means you know it's going to do the same thing every time so you're not afraid to actually do it and stay up to date. Using a revision control system like Git along with automated deployment recipes with Capistrano satisfies these criteria easily and gives your Rails app a little more oomph. Back to the Future on Rails This article assumes you're using a setup like I outlined in my article on how to setup a production server. That is, a Unix server with SSH access using Phusion Passenger and Apache serving a Ruby on Rails app. Knowing is half the battl...

Generate ERD diagrams for rails3 or highrer versions ? 1)install sudo aptitude install graphviz 2)Add gem "rails-erd" to your application's Gemfile 3)bundle install 4)bundle exec erd Another Method 1)gem install railroad 2)railroad -C | neato -Tpng > controllers.png Controller diagram in PNG format 3)railroad -M | neato -Tpng > models.png Model diagram in PNG format railroad -M | dot -Tsvg > models.svg Model diagram in SVG format 4)railroad -h

Deploying Rails app using Nginx, Unicorn, Postgres and Capistrano to Digital Ocean? Create droplet of your liking (ubuntu 12.10 x32) ssh to root in terminal with your server ip ssh root<a href="/123">@123</a>.123.123.123 Add ssh fingerprint and enter password provided Change password passwd Create new user adduser username Set new users privileges visudo Find user privileges section # User privilege specification root  ALL=(ALL:ALL) ALL Add your new user privileges under root & cntrl+x then y to save username ALL=(ALL:ALL) ALL Configure SSH nano /etc/ssh/sshd_config Find and change port to one that isn't default(22 is default: choose between 1025..65536) Port 22 # change this to whatever port you wish to use Protocol 2 PermitRootLogin no Add to bottom of sshd_config file after changing port (cntrl+x then y to save) UseDNS no AllowUsers username Reload ssh reload ssh Don't close root! Open new shell and ssh to vps with new username(remember the port...