# File lib/active_record/query_cache.rb, line 47
    def self.connection=(spec)
      raise ConnectionNotEstablished unless spec

      conn = spec.config[:query_cache] ?
        QueryCache.new(self.send(spec.adapter_method, spec.config)) :
        self.send(spec.adapter_method, spec.config)
      
      active_connections[self] = conn
    end