Module: Rails::Generators::Migration

Extended by:
ActiveSupport::Concern
Included in:
ActiveRecord::Generators::Base
Defined in:
railties/lib/rails/generators/migration.rb

Overview

Holds common methods for migrations. It assumes that migrations has the [0-9]*_name format and can be used by another frameworks (like Sequel) just by implementing the next migration version method.

Defined Under Namespace

Modules: ClassMethods

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from ActiveSupport::Concern

append_features, extended, included

Instance Attribute Details

#migration_class_nameObject (readonly)

Returns the value of attribute migration_class_name


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# File 'railties/lib/rails/generators/migration.rb', line 10

def migration_class_name
  @migration_class_name
end

#migration_file_nameObject (readonly)

Returns the value of attribute migration_file_name


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# File 'railties/lib/rails/generators/migration.rb', line 10

def migration_file_name
  @migration_file_name
end

#migration_numberObject (readonly)

Returns the value of attribute migration_number


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# File 'railties/lib/rails/generators/migration.rb', line 10

def migration_number
  @migration_number
end

Instance Method Details

#migration_template(source, destination = nil, config = {}) ⇒ Object

Creates a migration template at the given destination. The difference to the default template method is that the migration version is appended to the destination file name.

The migration version, migration file name, migration class name are available as instance variables in the template to be rendered.

migration_template "migration.rb", "db/migrate/add_foo_to_bar.rb"

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# File 'railties/lib/rails/generators/migration.rb', line 40

def migration_template(source, destination=nil, config={})
  destination = File.expand_path(destination || source, self.destination_root)

  migration_dir = File.dirname(destination)
  @migration_number     = self.class.next_migration_number(migration_dir)
  @migration_file_name  = File.basename(destination).sub(/\.rb$/, '')
  @migration_class_name = @migration_file_name.camelize

  destination = self.class.migration_exists?(migration_dir, @migration_file_name)

  if !(destination && options[:skip]) && behavior == :invoke
    if destination && options.force?
      remove_file(destination)
    elsif destination
      raise Error, "Another migration is already named #{@migration_file_name}: #{destination}. Use --force to remove the old migration file and replace it."
    end
    destination = File.join(migration_dir, "#{@migration_number}_#{@migration_file_name}.rb")
  end

  template(source, destination, config)
end