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) 


161
162
163
164
165
 
# File 'lib/active_record/migration.rb', line 161

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

Class Method Details

.current_version ⇒ Object 



156
157
158
 
# File 'lib/active_record/migration.rb', line 156

def current_version
  Base.connection.select_one("SELECT version FROM schema_info")["version"].to_i
end

.down(migrations_path, target_version = nil) ⇒ Object 



152
153
154
 
# File 'lib/active_record/migration.rb', line 152

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

.migrate(migrations_path, target_version = nil) ⇒ Object 



137
138
139
140
141
142
143
144
145
146
 
# File 'lib/active_record/migration.rb', line 137

def migrate(migrations_path, target_version = nil)
  case
    when target_version.nil?, current_version < target_version
      up(migrations_path, target_version)
    when current_version > target_version
      down(migrations_path, target_version)
    when current_version == target_version
      return # You're on the right version
  end
end

.up(migrations_path, target_version = nil) ⇒ Object 



148
149
150
 
# File 'lib/active_record/migration.rb', line 148

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

Instance Method Details

#current_version ⇒ Object 



167
168
169
 
# File 'lib/active_record/migration.rb', line 167

def current_version
  self.class.current_version
end

#migrate ⇒ Object 



171
172
173
174
175
176
177
178
179
180
 
# File 'lib/active_record/migration.rb', line 171

def migrate
  migration_classes.each do |(version, migration_class)|
    Base.logger.info("Reached target version: #{@target_version}") and break if reached_target_version?(version)
    next if irrelevant_migration?(version)

    Base.logger.info "Migrating to #{migration_class} (#{version})"
    migration_class.send(@direction)
    set_schema_version(version)
  end
end