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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 Rails commands 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

[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:schema:dump It can be used as a string/array (the typical case) or a hash (when you use multiple adapters) Example:

ActiveRecord::Tasks::DatabaseTasks.structure_dump_flags = {
  mysql2: ['--no-defaults', '--skip-add-drop-table'],
  postgres: '--no-tablespaces'
}

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 48
mattr_accessor :structure_dump_flags, instance_accessor: false

structure_load_flags

Extra flags passed to database CLI tool when calling db:schema:load It can be used as a string/array (the typical case) or a hash (when you use multiple adapters)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 54
mattr_accessor :structure_load_flags, instance_accessor: false

Instance Public methods

cache_dump_filename(db_config_name, schema_cache_path: nil)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 470
def cache_dump_filename(db_config_name, schema_cache_path: nil)
  filename = if ActiveRecord::Base.configurations.primary?(db_config_name)
    "schema_cache.yml"
  else
    "#{db_config_name}_schema_cache.yml"
  end

  schema_cache_path || ENV["SCHEMA_CACHE"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, filename)
end

charset(configuration, *arguments)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 324
def charset(configuration, *arguments)
  db_config = resolve_configuration(configuration)
  database_adapter_for(db_config, *arguments).charset
end

charset_current(env_name = env, db_name = name)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 319
def charset_current(env_name = env, db_name = name)
  db_config = configs_for(env_name: env_name, name: db_name)
  charset(db_config)
end

check_protected_environments!()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 63
def check_protected_environments!
  unless ENV["DISABLE_DATABASE_ENVIRONMENT_CHECK"]
    current = ActiveRecord::Base.connection.migration_context.current_environment
    stored  = ActiveRecord::Base.connection.migration_context.last_stored_environment

    if ActiveRecord::Base.connection.migration_context.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)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 487
def check_schema_file(filename)
  unless File.exist?(filename)
    message = +%{#{filename} doesn't exist yet. Run `bin/rails db:migrate` to create it, then try again.}
    message << %{ 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

check_target_version()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 309
def check_target_version
  if target_version && !(Migration::MigrationFilenameRegexp.match?(ENV["VERSION"]) || /\A\d+\z/.match?(ENV["VERSION"]))
    raise "Invalid format of target version: `VERSION=#{ENV['VERSION']}`"
  end
end

clear_schema_cache(filename)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 513
def clear_schema_cache(filename)
  FileUtils.rm_f filename, verbose: false
end

collation(configuration, *arguments)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 334
def collation(configuration, *arguments)
  db_config = resolve_configuration(configuration)
  database_adapter_for(db_config, *arguments).collation
end

collation_current(env_name = env, db_name = name)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 329
def collation_current(env_name = env, db_name = name)
  db_config = configs_for(env_name: env_name, name: db_name)
  collation(db_config)
end

create(configuration, *arguments)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 120
def create(configuration, *arguments)
  db_config = resolve_configuration(configuration)
  database_adapter_for(db_config, *arguments).create
  $stdout.puts "Created database '#{db_config.database}'" if verbose?
rescue DatabaseAlreadyExists
  $stderr.puts "Database '#{db_config.database}' already exists" if verbose?
rescue Exception => error
  $stderr.puts error
  $stderr.puts "Couldn't create '#{db_config.database}' database. Please check your configuration."
  raise
end

create_all()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 132
def create_all
  old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
  each_local_configuration { |db_config| create(db_config) }
  if old_pool
    ActiveRecord::Base.connection_handler.establish_connection(old_pool.db_config)
  end
end

create_current(environment = env, name = nil)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 183
def create_current(environment = env, name = nil)
  each_current_configuration(environment, name) { |db_config| create(db_config) }
  ActiveRecord::Base.establish_connection(environment.to_sym)
end

db_dir()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 88
def db_dir
  @db_dir ||= Rails.application.config.paths["db"].first
end

drop(configuration, *arguments)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 222
def drop(configuration, *arguments)
  db_config = resolve_configuration(configuration)
  database_adapter_for(db_config, *arguments).drop
  $stdout.puts "Dropped database '#{db_config.database}'" if verbose?
rescue ActiveRecord::NoDatabaseError
  $stderr.puts "Database '#{db_config.database}' does not exist"
rescue Exception => error
  $stderr.puts error
  $stderr.puts "Couldn't drop database '#{db_config.database}'"
  raise
end

drop_all()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 234
def drop_all
  each_local_configuration { |db_config| drop(db_config) }
end

drop_current(environment = env)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 238
def drop_current(environment = env)
  each_current_configuration(environment) { |db_config| drop(db_config) }
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")

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 509
def dump_schema_cache(conn, filename)
  conn.schema_cache.dump_to(filename)
end

env()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 108
def env
  @env ||= Rails.env
end

fixtures_path()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 96
def fixtures_path
  @fixtures_path ||= if ENV["FIXTURES_PATH"]
    File.join(root, ENV["FIXTURES_PATH"])
  else
    File.join(root, "test", "fixtures")
  end
end

for_each(databases)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 154
def for_each(databases)
  return {} unless defined?(Rails)

  database_configs = ActiveRecord::DatabaseConfigurations.new(databases).configs_for(env_name: Rails.env)

  # if this is a single database application we don't want tasks for each primary database
  return if database_configs.count == 1

  database_configs.each do |db_config|
    next unless db_config.database_tasks?

    yield db_config.name
  end
end

load_schema_current(format = ActiveRecord.schema_format, file = nil, environment = env)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 480
def load_schema_current(format = ActiveRecord.schema_format, file = nil, environment = env)
  each_current_configuration(environment) do |db_config|
    load_schema(db_config, format, file)
  end
  ActiveRecord::Base.establish_connection(environment.to_sym)
end

load_seed()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 495
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(version = nil)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 256
def migrate(version = nil)
  check_target_version

  scope = ENV["SCOPE"]
  verbose_was, Migration.verbose = Migration.verbose, verbose?

  Base.connection.migration_context.migrate(target_version) do |migration|
    if version.blank?
      scope.blank? || scope == migration.scope
    else
      migration.version == version
    end
  end.tap do |migrations_ran|
    Migration.write("No migrations ran. (using #{scope} scope)") if scope.present? && migrations_ran.empty?
  end

  ActiveRecord::Base.clear_cache!
ensure
  Migration.verbose = verbose_was
end

migrate_status()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 294
def migrate_status
  unless ActiveRecord::Base.connection.schema_migration.table_exists?
    Kernel.abort "Schema migrations table does not exist yet."
  end

  # output
  puts "\ndatabase: #{ActiveRecord::Base.connection_db_config.database}\n\n"
  puts "#{'Status'.center(8)}  #{'Migration ID'.ljust(14)}  Migration Name"
  puts "-" * 50
  ActiveRecord::Base.connection.migration_context.migrations_status.each do |status, version, name|
    puts "#{status.center(8)}  #{version.ljust(14)}  #{name}"
  end
  puts
end

migrations_paths()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 92
def migrations_paths
  @migrations_paths ||= Rails.application.paths["db/migrate"].to_a
end

name()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 112
def name
  @name ||= "primary"
end

prepare_all()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 188
def prepare_all
  seed = false

  each_current_configuration(env) do |db_config|
    ActiveRecord::Base.establish_connection(db_config)

    begin
      # Skipped when no database
      migrate

      if ActiveRecord.dump_schema_after_migration
        dump_schema(db_config, ActiveRecord.schema_format)
      end
    rescue ActiveRecord::NoDatabaseError
      create(db_config)

      if File.exist?(schema_dump_path(db_config))
        load_schema(
          db_config,
          ActiveRecord.schema_format,
          nil
        )
      else
        migrate
      end

      seed = true
    end
  end

  ActiveRecord::Base.establish_connection
  load_seed if seed
end

purge(configuration)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 339
def purge(configuration)
  db_config = resolve_configuration(configuration)
  database_adapter_for(db_config).purge
end

purge_all()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 344
def purge_all
  each_local_configuration { |db_config| purge(db_config) }
end

purge_current(environment = env)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 348
def purge_current(environment = env)
  each_current_configuration(environment) { |db_config| purge(db_config) }
  ActiveRecord::Base.establish_connection(environment.to_sym)
end

raise_for_multi_db(environment = env, command:)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 169
def raise_for_multi_db(environment = env, command:)
  db_configs = configs_for(env_name: environment)

  if db_configs.count > 1
    dbs_list = []

    db_configs.each do |db|
      dbs_list << "#{command}:#{db.name}"
    end

    raise "You're using a multiple database application. To use `#{command}` you must run the namespaced task with a VERSION. Available tasks are #{dbs_list.to_sentence}."
  end
end

register_task(pattern, task)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 79
def register_task(pattern, task)
  @tasks ||= {}
  @tasks[pattern] = task
end

root()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 104
def root
  @root ||= Rails.root
end

schema_dump_path(db_config, format = ActiveRecord.schema_format)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 457
def schema_dump_path(db_config, format = ActiveRecord.schema_format)
  return ENV["SCHEMA"] if ENV["SCHEMA"]

  filename = db_config.schema_dump(format)
  return unless filename

  if File.dirname(filename) == ActiveRecord::Tasks::DatabaseTasks.db_dir
    filename
  else
    File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, filename)
  end
end

schema_file_type(format = ActiveRecord.schema_format)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 447
def schema_file_type(format = ActiveRecord.schema_format)
  case format
  when :ruby
    "schema.rb"
  when :sql
    "structure.sql"
  end
end

schema_up_to_date?(configuration, format = ActiveRecord.schema_format, file = nil)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 390
def schema_up_to_date?(configuration, format = ActiveRecord.schema_format, file = nil)
  db_config = resolve_configuration(configuration)

  file ||= schema_dump_path(db_config)

  return true unless file && File.exist?(file)

  ActiveRecord::Base.establish_connection(db_config)

  return false unless ActiveRecord::InternalMetadata.enabled?
  return false unless ActiveRecord::InternalMetadata.table_exists?

  ActiveRecord::InternalMetadata[:schema_sha1] == schema_sha1(file)
end

seed_loader()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 116
def seed_loader
  @seed_loader ||= Rails.application
end

setup_initial_database_yaml()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 140
def setup_initial_database_yaml
  return {} unless defined?(Rails)

  begin
    Rails.application.config.load_database_yaml
  rescue
    unless ActiveRecord.suppress_multiple_database_warning
      $stderr.puts "Rails couldn't infer whether you are using multiple databases from your database.yml and can't generate the tasks for the non-primary databases. If you'd like to use this feature, please simplify your ERB."
    end

    {}
  end
end

structure_dump(configuration, *arguments)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 353
def structure_dump(configuration, *arguments)
  db_config = resolve_configuration(configuration)
  filename = arguments.delete_at(0)
  flags = structure_dump_flags_for(db_config.adapter)
  database_adapter_for(db_config, *arguments).structure_dump(filename, flags)
end

structure_load(configuration, *arguments)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 360
def structure_load(configuration, *arguments)
  db_config = resolve_configuration(configuration)
  filename = arguments.delete_at(0)
  flags = structure_load_flags_for(db_config.adapter)
  database_adapter_for(db_config, *arguments).structure_load(filename, flags)
end

target_version()

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 315
def target_version
  ENV["VERSION"].to_i if ENV["VERSION"] && !ENV["VERSION"].empty?
end

truncate_all(environment = env)

Source: show | on GitHub 

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 250
def truncate_all(environment = env)
  configs_for(env_name: environment).each do |db_config|
    truncate_tables(db_config)
  end
end