A Question about Model and Database?

[ACK]

hi i m new to rails i need to know the => which is the best way to create Database table in Rails?

1) rails generate model User name:string email:string
this will create a migration file with something like this

class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string :name # see here name column is already made becoz we have passed a parameters
      t.string :email # same as above

      t.timestamps
    end
  end
end

this is one method

2) rails generate model Page
this will create a empty migration file something like this

class CreatePages < ActiveRecord::Migration
  def change
    create_table :users do |t|
      ===>>  now we can add here like t.string "name" to create column manually ========>>>>>
      t.timestamps
    end
  end
end

So which is the good way to do above things example 1 or example 2?
Please tell.

and if i have to write a drop_table method in migration, can i write in the way which i showed below

class CreateSubjects < ActiveRecord::Migration
  def change
    create_table :subjects do |t|
      t.string "name"
     
      t.timestamps
    end
  end
 
  def self.down
    drop_table :subjects
  end
end

So again same question which is the good way to do above things example 1 ( model with parameter ) or example 2 ( model without parameter )?
Thanks for Taking Time to Read.

[ANIKET KADAM]

please  help me

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To post to this group, send email to rubyonra...@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-ta...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/WsDhrCEK-u8J.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

[Javier Quarite]

Rails is smart enough to determine if you want to create or drop a table if you have done the migration with change

def change

  #code here

end

it only depends on how you write the commands

if you do 

  rake db:migrate

then it will create the db (if the code inside change is about it) and if you do

  rake db:rollback 

it will drop that table

in other case then

def up

  #create table here

end

def down

  #drop table here

end

take a look here

http://guides.rubyonrails.org/migrations.html

and then here

http://stackoverflow.com/questions/10365129/rails-migrations-self-up-and-self-down-versus-change

http://stackoverflow.com/questions/7600415/rails-3-generate-migration-no-up-or-down-method

there is a lot more on google

JavierQ

[Fahim Patel]

use def change

forget up and down def

cheers

Fahim Babar Patel

--

You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To post to this group, send email to rubyonra...@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-ta...@googlegroups.com.

[ANIKET KADAM]

thanks for reply

On Sat, Sep 8, 2012 at 9:55 AM, Javier Quarite <jqua...@gmail.com> wrote:

--

You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To post to this group, send email to rubyonra...@googlegroups.com.
To unsubscribe from this group, send email to rubyonrails-ta...@googlegroups.com.

[Colin Law]

It is entirely up to you, do whichever you prefer.

Colin