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/Ruby on Rails 5.0

module ActiveRecord::ConnectionHandling

Constants

DEFAULT_ENV
RAILS_ENV

Attributes

connection_specification_name[W]

Public Instance Methods

connected?() Show source

Returns true if Active Record is connected.

# File activerecord/lib/active_record/connection_handling.rb, line 132
def connected?
  connection_handler.connected?(connection_specification_name)
end

connection() Show source

Returns the connection currently associated with the class. This can also be used to “borrow” the connection to do database work unrelated to any of the specific Active Records.

# File activerecord/lib/active_record/connection_handling.rb, line 90
def connection
  retrieve_connection
end

connection_config() Show source

Returns the configuration of the associated connection as a hash:

ActiveRecord::Base.connection_config
# => {pool: 5, timeout: 5000, database: "db/development.sqlite3", adapter: "sqlite3"}

Please use only for reading.

# File activerecord/lib/active_record/connection_handling.rb, line 119
def connection_config
  connection_pool.spec.config
end

connection_id() Show source

# File activerecord/lib/active_record/connection_handling.rb, line 105
def connection_id
  ActiveRecord::RuntimeRegistry.connection_id ||= Thread.current.object_id
end

connection_id=(connection_id) Show source

# File activerecord/lib/active_record/connection_handling.rb, line 109
def connection_id=(connection_id)
  ActiveRecord::RuntimeRegistry.connection_id = connection_id
end

connection_pool() Show source

# File activerecord/lib/active_record/connection_handling.rb, line 123
def connection_pool
  connection_handler.retrieve_connection_pool(connection_specification_name) or raise ConnectionNotEstablished
end

connection_specification_name() Show source

Return the specification id from this class otherwise look it up in the parent.

# File activerecord/lib/active_record/connection_handling.rb, line 98
def connection_specification_name
  if !defined?(@connection_specification_name) || @connection_specification_name.nil?
    return self == Base ? "primary" : superclass.connection_specification_name
  end
  @connection_specification_name
end

establish_connection(spec = nil) Show source

Establishes the connection to the database. Accepts a hash as input where the :adapter key must be specified with the name of a database adapter (in lower-case) example for regular databases (MySQL, PostgreSQL, etc):

ActiveRecord::Base.establish_connection(
  adapter:  "mysql2",
  host:     "localhost",
  username: "myuser",
  password: "mypass",
  database: "somedatabase"
)

Example for SQLite database:

ActiveRecord::Base.establish_connection(
  adapter:  "sqlite3",
  database: "path/to/dbfile"
)

Also accepts keys as strings (for parsing from YAML for example):

ActiveRecord::Base.establish_connection(
  "adapter"  => "sqlite3",
  "database" => "path/to/dbfile"
)

Or a URL:

ActiveRecord::Base.establish_connection(
  "postgres://myuser:mypass@localhost/somedatabase"
)

In case ActiveRecord::Base.configurations is set (Rails automatically loads the contents of config/database.yml into it), a symbol can also be given as argument, representing a key in the configuration hash:

ActiveRecord::Base.establish_connection(:production)

The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError may be returned on an error.

# File activerecord/lib/active_record/connection_handling.rb, line 47
def establish_connection(spec = nil)
  raise RuntimeError, "Anonymous class is not allowed." unless name

  spec     ||= DEFAULT_ENV.call.to_sym
  resolver =   ConnectionAdapters::ConnectionSpecification::Resolver.new configurations
  # TODO: uses name on establish_connection, for backwards compatibility
  spec     =   resolver.spec(spec, self == Base ? "primary" : name)

  unless respond_to?(spec.adapter_method)
    raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
  end

  remove_connection(spec.name)
  self.connection_specification_name = spec.name
  connection_handler.establish_connection spec
end

remove_connection(name = nil) Show source

# File activerecord/lib/active_record/connection_handling.rb, line 136
def remove_connection(name = nil)
  name ||= @connection_specification_name if defined?(@connection_specification_name)
  # if removing a connection that have a pool, we reset the
  # connection_specification_name so it will use the parent
  # pool.
  if connection_handler.retrieve_connection_pool(name)
    self.connection_specification_name = nil
  end

  connection_handler.remove_connection(name)
end

retrieve_connection() Show source

# File activerecord/lib/active_record/connection_handling.rb, line 127
def retrieve_connection
  connection_handler.retrieve_connection(connection_specification_name)
end