Class: Sequel::Migration

Inherits:
Object show all
Defined in:
lib/sequel/extensions/migration.rb

Overview

Sequel’s older migration class, available for backward compatibility. Uses subclasses with up and down instance methods for each migration:

Class.new(Sequel::Migration) do
  def up
    create_table(:artists) do
      primary_key :id
      String :name
    end
  end

  def down
    drop_table(:artists)
  end
end

Part of the migration extension.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(db) ⇒ Migration

Creates a new instance of the migration and sets the @db attribute.



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# File 'lib/sequel/extensions/migration.rb', line 25

def initialize(db)
  @db = db
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_sym, *args, &block) ⇒ Object

Intercepts method calls intended for the database and sends them along.



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# File 'lib/sequel/extensions/migration.rb', line 51

def method_missing(method_sym, *args, &block)
  @db.send(method_sym, *args, &block)
end

Class Method Details

.apply(db, direction) ⇒ Object

Applies the migration to the supplied database in the specified direction.

Raises:

  • (ArgumentError) 


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# File 'lib/sequel/extensions/migration.rb', line 31

def self.apply(db, direction)
  raise(ArgumentError, "Invalid migration direction specified (#{direction.inspect})") unless [:up, :down].include?(direction)
  new(db).send(direction)
end

.descendants ⇒ Object

Returns the list of Migration descendants.



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# File 'lib/sequel/extensions/migration.rb', line 37

def self.descendants
  @descendants ||= []
end

.inherited(base) ⇒ Object

Adds the new migration class to the list of Migration descendants.



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# File 'lib/sequel/extensions/migration.rb', line 42

def self.inherited(base)
  descendants << base
end

Instance Method Details

#down ⇒ Object

The default down action does nothing



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# File 'lib/sequel/extensions/migration.rb', line 47

def down
end

#up ⇒ Object

The default up action does nothing



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# File 'lib/sequel/extensions/migration.rb', line 56

def up
end