ActiveRecord::Tasks::DatabaseTasks is a utility class, which encapsulates logic behind common tasks used to manage database and migrations.

The tasks defined here are used with Rake tasks provided by Active Record.

In order to use DatabaseTasks, a few config values need to be set. All the needed config values are set by Rails already, so it's necessary to do it only if you want to change the defaults or when you want to use Active Record outside of Rails (in such case after configuring the database tasks, you can also use the rake tasks defined in Active Record).

The possible config values are:

  • env: current environment (like Rails.env).

  • database_configuration: configuration of your databases (as in config/database.yml).

  • db_dir: your db directory.

  • fixtures_path: a path to fixtures directory.

  • migrations_paths: a list of paths to directories with migrations.

  • seed_loader: an object which will load seeds, it needs to respond to the load_seed method.

  • root: a path to the root of the application.

Example usage of DatabaseTasks outside Rails could look as such:

include ActiveRecord::Tasks
DatabaseTasks.database_configuration = YAML.load_file('my_database_config.yml')
DatabaseTasks.db_dir = 'db'
# other settings...

DatabaseTasks.create_current('production')
Methods
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Constants
LOCAL_HOSTS = ["127.0.0.1", "localhost"]
 
Attributes
[W] current_config
[RW] database_configuration
[W] db_dir
[W] env
[W] fixtures_path
[W] migrations_paths
[W] root
[W] seed_loader
Class Public methods
structure_dump_flags

Extra flags passed to database CLI tool (mysqldump/pg_dump) when calling db:structure:dump

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 39
mattr_accessor :structure_dump_flags, instance_accessor: false
structure_load_flags

Extra flags passed to database CLI tool when calling db:structure:load

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 44
mattr_accessor :structure_load_flags, instance_accessor: false
Instance Public methods
charset(*arguments)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 183
def charset(*arguments)
  configuration = arguments.first
  class_for_adapter(configuration["adapter"]).new(*arguments).charset
end
charset_current(environment = env)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 179
def charset_current(environment = env)
  charset ActiveRecord::Base.configurations[environment]
end
check_protected_environments!()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 53
def check_protected_environments!
  unless ENV["DISABLE_DATABASE_ENVIRONMENT_CHECK"]
    current = ActiveRecord::Migrator.current_environment
    stored  = ActiveRecord::Migrator.last_stored_environment

    if ActiveRecord::Migrator.protected_environment?
      raise ActiveRecord::ProtectedEnvironmentError.new(stored)
    end

    if stored && stored != current
      raise ActiveRecord::EnvironmentMismatchError.new(current: current, stored: stored)
    end
  end
rescue ActiveRecord::NoDatabaseError
end
check_schema_file(filename)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 260
def check_schema_file(filename)
  unless File.exist?(filename)
    message = %Q{#{filename} doesn't exist yet. Run `rails db:migrate` to create it, then try again.}
    message << %Q{ If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded.} if defined?(::Rails.root)
    Kernel.abort message
  end
end
collation(*arguments)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 192
def collation(*arguments)
  configuration = arguments.first
  class_for_adapter(configuration["adapter"]).new(*arguments).collation
end
collation_current(environment = env)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 188
def collation_current(environment = env)
  collation ActiveRecord::Base.configurations[environment]
end
create(*arguments)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 115
def create(*arguments)
  configuration = arguments.first
  class_for_adapter(configuration["adapter"]).new(*arguments).create
  $stdout.puts "Created database '#{configuration['database']}'"
rescue DatabaseAlreadyExists
  $stderr.puts "Database '#{configuration['database']}' already exists"
rescue Exception => error
  $stderr.puts error
  $stderr.puts "Couldn't create database for #{configuration.inspect}"
  raise
end
create_all()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 127
def create_all
  old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
  each_local_configuration { |configuration| create configuration }
  if old_pool
    ActiveRecord::Base.connection_handler.establish_connection(old_pool.spec.to_hash)
  end
end
create_current(environment = env)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 135
def create_current(environment = env)
  each_current_configuration(environment) { |configuration|
    create configuration
  }
  ActiveRecord::Base.establish_connection(environment.to_sym)
end
current_config(options = {})
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 106
def current_config(options = {})
  options.reverse_merge! env: env
  if options.has_key?(:config)
    @current_config = options[:config]
  else
    @current_config ||= ActiveRecord::Base.configurations[options[:env]]
  end
end
db_dir()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 78
def db_dir
  @db_dir ||= Rails.application.config.paths["db"].first
end
drop(*arguments)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 142
def drop(*arguments)
  configuration = arguments.first
  class_for_adapter(configuration["adapter"]).new(*arguments).drop
  $stdout.puts "Dropped database '#{configuration['database']}'"
rescue ActiveRecord::NoDatabaseError
  $stderr.puts "Database '#{configuration['database']}' does not exist"
rescue Exception => error
  $stderr.puts error
  $stderr.puts "Couldn't drop database '#{configuration['database']}'"
  raise
end
drop_all()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 154
def drop_all
  each_local_configuration { |configuration| drop configuration }
end
drop_current(environment = env)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 158
def drop_current(environment = env)
  each_current_configuration(environment) { |configuration|
    drop configuration
  }
end
dump_schema_cache(conn, filename)

Dumps the schema cache in YAML format for the connection into the file

Examples:

ActiveRecord::Tasks::DatabaseTasks.dump_schema_cache(ActiveRecord::Base.connection, "tmp/schema_dump.yaml")
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 282
def dump_schema_cache(conn, filename)
  conn.schema_cache.clear!
  conn.data_sources.each { |table| conn.schema_cache.add(table) }
  open(filename, "wb") { |f| f.write(YAML.dump(conn.schema_cache)) }
end
env()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 98
def env
  @env ||= Rails.env
end
fixtures_path()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 86
def fixtures_path
  @fixtures_path ||= if ENV["FIXTURES_PATH"]
    File.join(root, ENV["FIXTURES_PATH"])
  else
    File.join(root, "test", "fixtures")
  end
end
load_schema_current(format = ActiveRecord::Base.schema_format, file = nil, environment = env)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 253
def load_schema_current(format = ActiveRecord::Base.schema_format, file = nil, environment = env)
  each_current_configuration(environment) { |configuration|
    load_schema configuration, format, file
  }
  ActiveRecord::Base.establish_connection(environment.to_sym)
end
load_seed()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 268
def load_seed
  if seed_loader
    seed_loader.load_seed
  else
    raise "You tried to load seed data, but no seed loader is specified. Please specify seed "                  "loader with ActiveRecord::Tasks::DatabaseTasks.seed_loader = your_seed_loader\n"                  "Seed loader should respond to load_seed method"
  end
end
migrate()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 164
def migrate
  raise "Empty VERSION provided" if ENV["VERSION"] && ENV["VERSION"].empty?

  verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
  version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
  scope = ENV["SCOPE"]
  verbose_was, Migration.verbose = Migration.verbose, verbose
  Migrator.migrate(migrations_paths, version) do |migration|
    scope.blank? || scope == migration.scope
  end
  ActiveRecord::Base.clear_cache!
ensure
  Migration.verbose = verbose_was
end
migrations_paths()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 82
def migrations_paths
  @migrations_paths ||= Rails.application.paths["db/migrate"].to_a
end
purge(configuration)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 197
def purge(configuration)
  class_for_adapter(configuration["adapter"]).new(configuration).purge
end
purge_all()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 201
def purge_all
  each_local_configuration { |configuration|
    purge configuration
  }
end
purge_current(environment = env)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 207
def purge_current(environment = env)
  each_current_configuration(environment) { |configuration|
    purge configuration
  }
  ActiveRecord::Base.establish_connection(environment.to_sym)
end
register_task(pattern, task)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 69
def register_task(pattern, task)
  @tasks ||= {}
  @tasks[pattern] = task
end
root()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 94
def root
  @root ||= Rails.root
end
schema_file(format = ActiveRecord::Base.schema_format)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 244
def schema_file(format = ActiveRecord::Base.schema_format)
  case format
  when :ruby
    File.join(db_dir, "schema.rb")
  when :sql
    File.join(db_dir, "structure.sql")
  end
end
seed_loader()
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 102
def seed_loader
  @seed_loader ||= Rails.application
end
structure_dump(*arguments)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 214
def structure_dump(*arguments)
  configuration = arguments.first
  filename = arguments.delete_at 1
  class_for_adapter(configuration["adapter"]).new(*arguments).structure_dump(filename, structure_dump_flags)
end
structure_load(*arguments)
# File activerecord/lib/active_record/tasks/database_tasks.rb, line 220
def structure_load(*arguments)
  configuration = arguments.first
  filename = arguments.delete_at 1
  class_for_adapter(configuration["adapter"]).new(*arguments).structure_load(filename, structure_load_flags)
end