Schemer

On-the-fly schema changes for very rapid prototyping, for ActiveRecord and Sequel ORMs.

Loosely define your schema in your model and have it created and updated for you without worrying about migrations.

Useful for when you want to play around with real data handling during prototyping but you really don't care about keeping the data or how it's defined.

This isn't meant to be a replacement for migrations, it is simply a way to get started on a project quickly while you iron out your data definitions.

WARNING: This will create and delete data definitions on the fly with no warning! Only use this with volatile data! Never attach it to an existing model you care about as it will start adding and dropping columns without your consent!

$ gem install schemer

require "schemer/active_record"

class User < ActiveRecord::Base
  schema :username, :password
end

Creates a users table if it doesn't exist, complete with username and password columns the first time the User class is loaded.

Need another column to play with?

class User < ActiveRecord::Base
  schema :username, :password, :email
end

Adds an email column the next time User class is loaded.

Want a relationship? (but fear commitment...)

class Widget < ActiveRecord::Base
  schema :user_id, :name

  belongs_to :user
end

Works just fine, and you can drop it at any time!

class Widget < ActiveRecord::Base
  schema :name
end

Removes the user_id column the next time the Widget class is loaded.

Have a need for a particular type of column?

class Widget < ActiveRecord::Base
  schema :name, { :size => :integer }, :description
end

Will create size as an :integer column so you can take advantage of type loading.

Feeling more confident and ready to make that big leap to migrations? Run:

rake schemer:migration

To get:

Migration from schema declarations in User, Widget

create_table :users do |t|
  t.string :username
  t.string :password
  t.string :email
end

create_table :widgets do |t|
  t.string :name
  t.integer :size
  t.string :description
end

Then you can paste the output into a migration file, setup your columns (don't forget your indexes!) and get rid of your schema calls in the listed classes and you're on your way to the big leagues!

NOTE: All columns are created as string columns unless type is given.

require "schemer/sequel"

class Widget < Sequel::Model
  plugin Schemer::Sequel
  
  schema :name, { :size => :integer }, :description
end

Usage is as above w/ ActiveRecord

$ rake

Michel Martens (soveran) + Cyril David (cyx) for helping with Sequel support.

Copyright (c) 2009-2011 Ben Alavi for Citrusbyte

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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