ActiveRecord::ConnectionHandling

Methods

connected?
connection
connection_config
connection_pool
connection_specification_name
establish_connection
remove_connection
retrieve_connection

Constants

DEFAULT_ENV	=	-> { RAILS_ENV.call \|\| "default_env" }
RAILS_ENV	=	-> { (Rails.env if defined?(Rails.env)) \|\| ENV["RAILS_ENV"].presence \|\| ENV["RACK_ENV"].presence }

Attributes

[W]

connection_specification_name

Instance Public methods

connected?()

Returns true if Active Record is connected.

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 122
    def connected?
      connection_handler.connected?(connection_specification_name)
    end

🔎 See on GitHub

connection()

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.

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 89
    def connection
      retrieve_connection
    end

🔎 See on GitHub

connection_config()

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.

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 109
    def connection_config
      connection_pool.spec.config
    end

🔎 See on GitHub

connection_pool()

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 113
    def connection_pool
      connection_handler.retrieve_connection_pool(connection_specification_name) || raise(ConnectionNotEstablished)
    end

🔎 See on GitHub

connection_specification_name()

Return the specification name from the current class or its parent.

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 96
    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

🔎 See on GitHub

establish_connection(config = nil)

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.

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 49
    def establish_connection(config = nil)
      raise "Anonymous class is not allowed." unless name

      config ||= DEFAULT_ENV.call.to_sym
      spec_name = self == Base ? "primary" : name
      self.connection_specification_name = spec_name

      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(Base.configurations)
      spec = resolver.resolve(config).symbolize_keys
      spec[:name] = spec_name

      connection_handler.establish_connection(spec)
    end

🔎 See on GitHub

remove_connection(name = nil)

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 126
    def remove_connection(name = nil)
      name ||= @connection_specification_name if defined?(@connection_specification_name)
      # if removing a connection that has 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

🔎 See on GitHub

retrieve_connection()

📝 Source code

# File activerecord/lib/active_record/connection_handling.rb, line 117
    def retrieve_connection
      connection_handler.retrieve_connection(connection_specification_name)
    end

🔎 See on GitHub