def self.establish_connection(spec = nil)
case spec
when nil
raise AdapterNotSpecified unless defined? RAILS_ENV
establish_connection(RAILS_ENV)
when ConnectionSpecification
@@connection_handler.establish_connection(name, spec)
when Symbol, String
if configuration = configurations[spec.to_s]
establish_connection(configuration)
else
raise AdapterNotSpecified, "#{spec} database is not configured"
end
else
spec = spec.symbolize_keys
unless spec.key?(:adapter) then raise AdapterNotSpecified, "database configuration does not specify adapter" end
begin
require 'rubygems'
gem "activerecord-#{spec[:adapter]}-adapter"
require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
rescue LoadError
begin
require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
rescue LoadError
raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{$!})"
end
end
adapter_method = "#{spec[:adapter]}_connection"
if !respond_to?(adapter_method)
raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter"
end
remove_connection
establish_connection(ConnectionSpecification.new(spec, adapter_method))
end
end