Class: ActiveRecord::Migrator

Inherits:
Object
  • Object
show all
Defined in:
lib/active_record/migration.rb

Overview

:nodoc:

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(direction, migrations_path, target_version = nil) ⇒ Migrator

Returns a new instance of Migrator.

Raises:

  • (StandardError) 


407
408
409
410
411
 
# File 'lib/active_record/migration.rb', line 407

def initialize(direction, migrations_path, target_version = nil)
  raise StandardError.new("This database does not yet support migrations") unless Base.connection.supports_migrations?
  Base.connection.initialize_schema_migrations_table
  @direction, @migrations_path, @target_version = direction, migrations_path, target_version      
end

Class Method Details

.current_version ⇒ Object 



392
393
394
395
396
397
398
399
 
# File 'lib/active_record/migration.rb', line 392

def current_version
  sm_table = schema_migrations_table_name
  if Base.connection.table_exists?(sm_table)
    get_all_versions.max || 0
  else
    0
  end
end

.down(migrations_path, target_version = nil) ⇒ Object 



376
377
378
 
# File 'lib/active_record/migration.rb', line 376

def down(migrations_path, target_version = nil)
  self.new(:down, migrations_path, target_version).migrate
end

.get_all_versions ⇒ Object 



388
389
390
 
# File 'lib/active_record/migration.rb', line 388

def get_all_versions
  Base.connection.select_values("SELECT version FROM #{schema_migrations_table_name}").map(&:to_i).sort
end

.migrate(migrations_path, target_version = nil) ⇒ Object 



354
355
356
357
358
359
360
 
# File 'lib/active_record/migration.rb', line 354

def migrate(migrations_path, target_version = nil)
  case
    when target_version.nil?              then up(migrations_path, target_version)
    when current_version > target_version then down(migrations_path, target_version)
    else                                       up(migrations_path, target_version)
  end
end

.proper_table_name(name) ⇒ Object 



401
402
403
404
 
# File 'lib/active_record/migration.rb', line 401

def proper_table_name(name)
  # Use the Active Record objects own table_name, or pre/suffix from ActiveRecord::Base if name is a symbol/string
  name.table_name rescue "#{ActiveRecord::Base.table_name_prefix}#{name}#{ActiveRecord::Base.table_name_suffix}"
end

.rollback(migrations_path, steps = 1) ⇒ Object 



362
363
364
365
366
367
368
369
370
 
# File 'lib/active_record/migration.rb', line 362

def rollback(migrations_path, steps=1)
  migrator = self.new(:down, migrations_path)
  start_index = migrator.migrations.index(migrator.current_migration)
  
  return unless start_index
  
  finish = migrator.migrations[start_index + steps]
  down(migrations_path, finish ? finish.version : 0)
end

.run(direction, migrations_path, target_version) ⇒ Object 



380
381
382
 
# File 'lib/active_record/migration.rb', line 380

def run(direction, migrations_path, target_version)
  self.new(direction, migrations_path, target_version).run
end

.schema_migrations_table_name ⇒ Object 



384
385
386
 
# File 'lib/active_record/migration.rb', line 384

def schema_migrations_table_name
  Base.table_name_prefix + 'schema_migrations' + Base.table_name_suffix
end

.up(migrations_path, target_version = nil) ⇒ Object 



372
373
374
 
# File 'lib/active_record/migration.rb', line 372

def up(migrations_path, target_version = nil)
  self.new(:up, migrations_path, target_version).migrate
end

Instance Method Details

#current_migration ⇒ Object 



417
418
419
 
# File 'lib/active_record/migration.rb', line 417

def current_migration
  migrations.detect { |m| m.version == current_version }
end

#current_version ⇒ Object 



413
414
415
 
# File 'lib/active_record/migration.rb', line 413

def current_version
  migrated.last || 0
end

#migrate ⇒ Object 



430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
 
# File 'lib/active_record/migration.rb', line 430

def migrate
  current = migrations.detect { |m| m.version == current_version }
  target = migrations.detect { |m| m.version == @target_version }

  if target.nil? && !@target_version.nil? && @target_version > 0
    raise UnknownMigrationVersionError.new(@target_version)
  end
  
  start = up? ? 0 : (migrations.index(current) || 0)
  finish = migrations.index(target) || migrations.size - 1
  runnable = migrations[start..finish]
  
  # skip the last migration if we're headed down, but not ALL the way down
  runnable.pop if down? && !target.nil?
  
  runnable.each do |migration|
    Base.logger.info "Migrating to #{migration} (#{migration.version})"

    # On our way up, we skip migrating the ones we've already migrated
    # On our way down, we skip reverting the ones we've never migrated
    next if up? && migrated.include?(migration.version.to_i)

    if down? && !migrated.include?(migration.version.to_i)
      migration.announce 'never migrated, skipping'; migration.write
    else
      migration.migrate(@direction)
      record_version_state_after_migrating(migration.version)
    end
  end
end

#migrated ⇒ Object 



497
498
499
 
# File 'lib/active_record/migration.rb', line 497

def migrated
  @migrated_versions ||= self.class.get_all_versions
end

#migrations ⇒ Object 



461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
 
# File 'lib/active_record/migration.rb', line 461

def migrations
  @migrations ||= begin
    files = Dir["#{@migrations_path}/[0-9]*_*.rb"]
    
    migrations = files.inject([]) do |klasses, file|
      version, name = file.scan(/([0-9]+)_([_a-z0-9]*).rb/).first
      
      raise IllegalMigrationNameError.new(file) unless version
      version = version.to_i
      
      if klasses.detect { |m| m.version == version }
        raise DuplicateMigrationVersionError.new(version) 
      end

      if klasses.detect { |m| m.name == name.camelize }
        raise DuplicateMigrationNameError.new(name.camelize) 
      end
      
      load(file)
      
      klasses << returning(name.camelize.constantize) do |klass|
        class << klass; attr_accessor :version end
        klass.version = version
      end
    end
    
    migrations = migrations.sort_by(&:version)
    down? ? migrations.reverse : migrations
  end
end

#pending_migrations ⇒ Object 



492
493
494
495
 
# File 'lib/active_record/migration.rb', line 492

def pending_migrations
  already_migrated = migrated
  migrations.reject { |m| already_migrated.include?(m.version.to_i) }
end

#run ⇒ Object

Raises:



421
422
423
424
425
426
427
428
 
# File 'lib/active_record/migration.rb', line 421

def run
  target = migrations.detect { |m| m.version == @target_version }
  raise UnknownMigrationVersionError.new(@target_version) if target.nil?
  unless (up? && migrated.include?(target.version.to_i)) || (down? && !migrated.include?(target.version.to_i))
    target.migrate(@direction)
    record_version_state_after_migrating(target.version)
  end
end