Writing a Scope containing a method - Rails 4 -

-

i new rails , or advise appreciated

  • i trying write scope displays users ratings equal or greater 4. unsure why scope not working , appreciated

user.rb

scope :ratings_equal_and_greater_than_4, where('average_rating_final_score >= 4')  def average_rating_final_score     if self.average_rating_score == 1.0       1     elsif self.average_rating_score == 2.0       2     elsif self.average_rating_score == 3.0       3     elsif self.average_rating_score == 4.0       4     elsif self.average_rating_score == 5.0       5     else       self.average_rating_score     end       end    def average_rating_score     ratings_total.to_f / ratings_count   end

the scope works when written this:

<% if user.average_rating_final_score >= 4 %>    # display users ratings equal or greater 4 star <% end %>

but write in views

@users.ratings_equal_and_greater_than_4

could 1 kindly advise me how write correctly scope

rails scopes arel - kind of ruby wrapped sql. it's mean can't call ruby code sql statement this:

where('average_rating_final_score >= 4')

but can define class method work want:

def self.ratings_equal_and_greater_than_4   all.reject{ |record| record.average_rating_final_score < 4 } end

also can write propper sql query:

where('(`table_name.ratings_total` / `table_name.ratings_count`) >= 4')

Comments

Post a Comment

Popular posts from this blog

ios - Memory not freeing up after popping viewcontroller using ARC -

-
hi project arc based, using uinavigationcontroller make transition between viewcontroller. using profiler analyse happening behind scene memory. noticed when push viewcontroller allocate memory components , when pop not freeing allocated memory. since using arc unable implement dealloc or release component. have analysed in detail , there no memory leak in project. i not using strong property push viewcontroller. here how pushing viewcontroller. viewcontroller *obj = [[viewcontroller alloc] init]; [self.navigationcontroller pushviewcontroller:obj animated:no]; any clue whats going on? should free memory have consumed. please advise your description indicates have retain cycle, leads objects not being deallocated. typical source of retain cycles properties assigned loading nib files (usually declared iboutlet ). two strategies break them , release objects: declare property weak : @property (nonatomic, weak) iboutlet uilabel *statuslabel; set property nil in...
Read more

Django REST Framework perform_create: You cannot call `.save()` after accessing `serializer.data` -

-
i have following viewset: class artistprofileviewset(viewsets.modelviewset): queryset = artistprofile.objects.all() serializer_class = artistprofileserializer def perform_create(self, serializer): if serializer.is_valid(): serializer.save() with following serializers: class simpleartisttrackserializer(serializers.hyperlinkedmodelserializer): class meta: model = artisttrack fields = (...my fields...) class artistprofileserializer(serializers.hyperlinkedmodelserializer): owners = userserializer(many=true, required=false) tracks = simpleartisttrackserializer(many=true, required=false) class meta: model = artistprofile fields = (...my fields...) i getting following error: assertionerror: cannot call `.save()` after accessing `serializer.data`.if need access data before committing database inspect 'serializer.validated_data' instead. i don't see editing serializer.data object. th...
Read more

Why does Go error when trying to marshal this JSON? -

-
i'm trying rather simple example of trying decode json file structs using golang. however, when attempting error that json: cannot unmarshal object go value of type []main.track which don't understand. here's code in question, , json can found here . package main import ( "encoding/json" "fmt" "net/http" "os" ) // tracks group of track types type tracks struct { tracks []track } // track represents singular track type track struct { name string url string artist artist } // artist represents single artist type artist struct { name string mbid string url string } func main() { url := "http://ws.audioscrobbler.com/2.0/?method=geo.gettoptracks&api_key=c1572082105bd40d247836b5c1819623&format=json&country=netherlands" response, err := http.get(url) if err != nil { fmt.printf("%s\n", err) os.exit(1) } de...
Read more