Module: SM

Defined in:
lib/entities/record.rb,
lib/super_migration.rb,
lib/entities/fields_map.rb

Defined Under Namespace

Classes: FieldsMap, Record, SuperMigration

Instance Method Summary collapse

Instance Method Details

#define_init_classes(from, to) ⇒ Object 



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# File 'lib/super_migration.rb', line 70

def define_init_classes(from, to)
  # create a class with the name table[:from] in the SM module
  # which inherits from ActiveRecord::Base
  # call the establish_connection method for this class
  
  SuperMigration.current_table_from = from.to_s.singularize.capitalize
  SM.class_eval("class #{SuperMigration.current_table_from} < ActiveRecord::Base ; establish_connection(SuperMigration.from_db_options) ; end")
  
  # create a class with the name table[:from] in the SM module
  # which inherits from ActiveRecord::Base
  # call the establish_connection nethod for this class
  
  SuperMigration.current_table_to = to.to_s.singularize.capitalize
  SM.class_eval("class #{SuperMigration.current_table_to} < ActiveRecord::Base ; establish_connection(SuperMigration.to_db_options); end")
end

#field(options = {}, &block) ⇒ Object 



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# File 'lib/super_migration.rb', line 122

def field(options = {}, &block)
  return if options.size < 2
  if block_given?
    raise "Arity for block is not good." if block.arity != 1
  end
  
  fields_map = FieldsMap.new(options[:from], options[:to], block)
  SuperMigration.current_record.fields_maps << fields_map
end

#table(table = {}, &block) ⇒ Object 



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# File 'lib/super_migration.rb', line 86

def table(table = {}, &block)
  return unless block_given?
  
  define_init_classes(table[:from], table[:to])
  
  puts "Migrating data from table #{table[:from]} to table #{table[:to]}"
  puts "-----------------------------------------------------------------"
  
  yield
  
  from_table = SuperMigration.current_table_from
  to_table   = SuperMigration.current_table_to
  
  Kernel.const_get(from_table).all.collect do |record| 
    rc = SuperMigration.current_record.dup
    new_record_hash = Hash.new
    
    rc.fields_maps.each do |field_map|
      unless record.respond_to?(field_map.from)
        raise "Undefined attribute name \"#{field_map.from}\" for Model #{from_table}."
      end
      
      if field_map.block
        new_record_hash[field_map.to] = field_map.block.call(record.send(field_map.from))
      else
        new_record_hash[field_map.to] = record.send(field_map.from)
      end
    end
    new_record = Kernel.const_get(to_table).new(new_record_hash)
    new_record.save!
  end
  
  # reinitialize current_record
  SuperMigration.current_record = Hash.new
end