activerecord - Rails, get record with has_and_belongs_to_many having more than one value -

-

given these models

modelone     has_and_belongs_to_many :model_twos  modeltwo     has_and_belongs_to_many :model_ones      field_one: string

how use active record modelones had associated modeltwos field_one equalled "value_1" , "value_2"

something modelone.joins(:model_twos).where(model_twos:{field_one: "value_1" , "value_2"})

this indeed tricky, if want use activerecord (i.e. without falling arel).

i'm not 100% work or produce desirable sql i'd try this:

class modelone < activerecord::base   scope :with_model_two_value, -> (val) { joins(:model_twos).where(model_twos: { field_one: val }) } end  modelone.with_model_two_value('value_1').merge(modelone.with_model_two_value('value_2'))

Comments

Post a Comment

Popular posts from this blog

mysql - Dreamhost PyCharm Django Python 3 Launching a Site -

-
i'm new python/django , created simple django website using pycharm. site works fine running on computer, i'm lost when comes taking site onto host (dreamhost). i'm able upload files correct directories fine, , believe made correct changes database on mysql. i'm not sure go there though. right now, page shows files rather site. direction appreciated. much! you should not run django application using python manage.py runserver on production. how run application on django depends on server (apache, nginx) want use for apache - https://docs.djangoproject.com/en/1.10/howto/deployment/wsgi/modwsgi/ for nginx - https://www.digitalocean.com/community/tutorials/how-to-serve-django-applications-with-uwsgi-and-nginx-on-ubuntu-14-04 the mysql database should, of course, exist , have correct credentials. or, if choose use sqlite, file should accessible, readable , writable www-user (may different depending on linux distributive)
Read more

java - Sending SMS with SMSLib and Web Services -

-
i have made rest web service send smss using hsdpa usb modem. using smslib in java send smss. every time web service invoked, create gateway start service, send message, stop service , remove gateway. takes 20 seconds each message. found starting service takes lot of time. part of code use send smss service.getinstance().addgateway(gateway); service.getinstance().startservice(); outboundmessage msg = new outboundmessage(phonenumber, message); if (service.getinstance().sendmessage(msg)) { result = "message sent successfully!!"; } else { result = "could not send message."; } service.getinstance().stopservice(); service.getinstance().removegateway(gateway);//remove gateway is there way can start service once if not started , use send message when ever web service invoked? why dont group messages , send in 1 go? service.getinstance().sendmessages(messa...
Read more

java - How to resolve The method toString() in the type Object is not applicable for the arguments (InputStream) -

-
i'm trying read json file local machine. @path("/") public class jsonparsing { file f = new file("file.json"); if (f.exists()){ inputstream = new fileinputstream("file.json"); string jsontxt = ioutils.tostring(is); system.out.println(jsontxt); jsonobject json = new jsonobject(jsontxt); string = json.getstring("1000"); system.out.println(a); } } but i'm getting error in tostring() method. possible read .txt file containing json object local machine? if possible, how done? firstly: whenever ask question- add imports well. secondly: yes possible read .txt file containing json object. steps: 1. add maven dependency in pom.xml - <dependency> <groupid>com.googlecode.json-simple</groupid> <artifactid>json-simple</artifactid> <version>1.1.1</version> </dependency> or add jar of dependency. 2.import...
Read more