def self.establish_connection(spec = nil)
case spec
when nil
raise AdapterNotSpecified unless defined?(Rails.env)
establish_connection(Rails.env)
when ConnectionSpecification
self.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 "active_record/connection_adapters/#{spec[:adapter]}_adapter"
rescue LoadError => e
raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{e})"
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