There were several occasions when I had to migrate the contents of a database into another database having a different schema. This happened especially when dealing with legacy databases.
I usually write a script which "maps" fields from one database to another when dealing with this kind of situation. Recently, I thought it would be a better idea to create a DLS where one would specify the mappings in a simpler way. So I started working on a gem that does this. Here is how the gem can be used for migrating the contents of a database to another.First, the super_migration gem needs to be installed:
gem install super_migration
require 'super_migration' include SM SuperMigration.setup do |config| config.from_database :database => "sm1", :adapter => "mysql", :host => "localhost", :username => "root", :password => "" config.to_database :database => "sm2", :adapter => "mysql", :host => "localhost", :username => "root", :password => "" end
SuperMigration.migrate do table :from => :books, :to => :livres do field :from => :author, :to => :autheur # apply a transformation to dob field field :from => :title, :to => :titre do |title| Date.today.to_s + title end end end
Then the file needs to be ran and the script will take care of the migration:
I plan to further enhance this gem so that it supports more options and transformations.