tutorials

tutorial: https://www.youtube.com/watch?v=lDpnaE724PA
Ruby:-
1-methods in ruby:-
a- to define a method --> def "methodName" --> method body --> end 
b-method with params def "methodName(param1,param2,..)

2- hashes in ruby:- 
hash:-user= {'first_name'=> 'john', 'last_name' => 'doe'}
array of hashes:- users=[{'first_name'=> 'john', 'last_name' => 'doe'}, {'first_name'=> 'omar', 'last_name' => 'essam'}]

3-loops in ruby:-
a- 5.times do puts "i am learning ruby" end
b- 5.times { puts "i am learning ruby" }
c-  3.upto(10) {puts "this is fun"} (inclusive)
d-  3.downto(2) {puts "this is fun"}
e- normal while loops
f-  planets= ["omar", "shadwa" ,"Nouran", "Mody", "Hariry"]
	planets.each{|x|puts x}

4- classes&objects in ruby
a- class Class_name
b- attr_accessor :attr1, :attr2,..
c- end
d- object1= Class_name.new
e- object2.attr1= ....
f- class sub_class < super_class (inheritance)
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Rails:-




1- to generate controllers "rails generate controller "controllerName" "viewName"

2- to change home page go to config/routes.rb and uncomment "root 'controller#homepage'"

3- after creating a controller head to routes.rb and give it the resources(edit, new, create, destroy, index, show, & update) by typing resources :"controllerName"

4- define these 7 methods in the controller file

5- then in the views folder create and .html.erb file for each one of these

6- to grab a variable from the controller define the variable in the method like this---> "@varName" 
eg: if you wanna grab a variable in the index file define that variable in the index method in the controller

 then just put that variable inside ruby tags <%= var name%> (the '=' is for showing that piece of code in the website)

7- to setup a model for your database type "rails g model modelName(HAS TO BE SINGULAR) column name:type"

8-to create the tables type rake db:migrate
	you should modify your files with relations 

9- to add new info to database open rails c

   then create an instance of the class with the required attributes  
   (as   a hash)
   after that typy instanceName.save

  or simply when creating an instance instead of className.new use 
  className.create

10- to find a certain element simple type tableName.find(index)

11- to update find first then found.update_attribute(:columnName, newValue) -->this is for updating a single value
and for multiple attributes found.update_attributes(:column1 =>newVal1, :column2 => newVal)

12- to show dynamic data define a variable in the controller get all data you wanna get then loop on them in the view

13- to show a specific post type @post= Post.find(params[:id]) and grab that in teh show fiie

14- to transfer to link link_to from,to

15- to allow access for certain parameters :-

  def user_params
    params.require(:user).permit(:username, :email, :password, :salt, :encrypted_password)
  end

16- to create a form:-
<h1>Add New Post</h1>
<%= form_for @post do |f| %>
<p>
<%= f.label :title %>
<br>
<%= f.text_field :title %> <br><br>
</p>

<p>
<%= f.select :category_id, Category.all.collect {|x| [x.name, x.id]}, {:include_blank => "Select One"} %> <br><br>
</p>

<p>
<%= f.label :body %>
<br>
<%= f.text_area :body %> <br><br>
</p>
<p> <%= f.submit "Add Post" %> </p>
<% end %>

 in the new action:-
@post= Post.new
in the create action:-
@post = Post.new(post_params)
		if @post.save
			redirect_to posts_path, :notice => "your post 
			has been saved"
		else 
			render "new"
		end

17- to pass a parameter when directing link_to c.name,categories_path(:name => c.name) 

18- to check if a variable exists params[...].blank?
add attribute to table
rails generate migration AddDetailsToArticle user_id:integer
conditioned find and order Bid.where({user_id:12, status:2 }).order(created_at: :desc)