module ActiveRecord::ConnectionHandling - activerecord-4.2.3 Documentation

# module ActiveRecord::ConnectionHandling

### Constants

DEFAULT_ENV
RAILS_ENV

### Public Instance Methods

connected?() click to toggle source

Returns `true` if Active Record is connected.

    # File lib/active_record/connection_handling.rb, line 117
    def connected?
      connection_handler.connected?(self)
    end

connection() click to toggle 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 lib/active_record/connection_handling.rb, line 86
    def connection
      retrieve_connection
    end

connection_config() click to toggle 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 lib/active_record/connection_handling.rb, line 104
    def connection_config
      connection_pool.spec.config
    end

connection_id() click to toggle source

    # File lib/active_record/connection_handling.rb, line 90
    def connection_id
      ActiveRecord::RuntimeRegistry.connection_id
    end

connection_id=(connection_id) click to toggle source

    # File lib/active_record/connection_handling.rb, line 94
    def connection_id=(connection_id)
      ActiveRecord::RuntimeRegistry.connection_id = connection_id
    end

connection_pool() click to toggle source

    # File lib/active_record/connection_handling.rb, line 108
    def connection_pool
      connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished
    end

establish_connection(spec = nil) click to toggle 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:  "mysql",
      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 lib/active_record/connection_handling.rb, line 47
    def establish_connection(spec = nil)
      spec     ||= DEFAULT_ENV.call.to_sym
      resolver =   ConnectionAdapters::ConnectionSpecification::Resolver.new configurations
      spec     =   resolver.spec(spec)

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

      remove_connection
      connection_handler.establish_connection self, spec
    end

remove_connection(klass = self) click to toggle source

    # File lib/active_record/connection_handling.rb, line 121
    def remove_connection(klass = self)
      connection_handler.remove_connection(klass)
    end

retrieve_connection() click to toggle source

    # File lib/active_record/connection_handling.rb, line 112
    def retrieve_connection
      connection_handler.retrieve_connection(self)
    end