Has Magic Columns

Allows the addition of “magic” columns and attributes on a per model basis.

Installation

You need to create table definitions for MagicColumns.

Generate the migration using the included task:

rake has_magic_columns:db:create

Run the standard migrate task to update your schema:

rake db:migrate

You’re ready to start using HasMagicColumns!

Example

class Person < ActiveRecord::Base has_magic_columns end

Create a Person @bob = Person.create(:email => “bob@example.com”)

Add some MagicColumns @bob.magic_columns << MagicColumn.create(:name => “first_name”) @bob.magic_columns << MagicColumn.create(:name => “last_name”) @bob.magic_columns << MagicColumn.create(:name => “birthday”, :datatype => “date”)

Give @bob some magic… @bob.first_name = “Bob” @bob.last_name = “Magic!” @bob.birthday = Date.today

Save @bob like normal @bob.save

Find @bob and inspect him @bob = Person.find(@bob.id) @bob.first_name #=> “Bob” @bob.last_name #=> “Magic!” @bob.birthday #=> #<date: 4908497 />

Inherit Template Columns

A child can “inherit” magic columns from its parent. You can use container models to provide a column template for contained objects. For example, an Account has_magic_columns and has_many :people. A Person inherits magic columns from its account:

class Person < ActiveRecord::Base belongs_to :account has_magic_columns :inherit => :account end

Children people now all share the columns of their parent account. You don’t need to use these magic columns on the Account of course. It’s just a convenient and logical way to provide column templating.

This is really nice in multi-user, multi-account environments where Accounts can “customize” model attributes.

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