I was wondering if someone could help me or point me to a tutorial to help me understand how to send the results of a rails query into a view? At the moment, I am only able to run a query using the console, but I'm not sure how to render the results into a view. For example, I have a model called City with the attributes state, population_size, and capital. For example, if I run a query in the console:
results = City.where(:state => 'Virginia')
How can I run that same query in Rails? Specifically, where would I place that code? Sorry for the noob question, but I can't find any guides that explicitly show me how to do this. I have only found guides on how to work in the console, but now how to actually render a view of the results...
Thanks!!
You can create the instance var to use it in your views
#results = City.where(:state => 'Virginia')
Now in your view you have access to #results
You can create the instance var to access it throughout the request.
if you want an array of results.
#results = City.where(:state => 'stateName')
if you want a single object
#result = City.find_by(state: 'stateName', id: :id)
Both can help you in different circumstances.
Now in your view you have access to #results
Related
I'm a Rails beginner, and have been reading tutorials and typing out applications for a few months now. I'm really enjoying it after a few years spent in the front end world, and beginning to get up to speed with it all. The time has come though for me to start building my own stuff without any handholding. So far, so good.
I'm creating a basic to-do list app, where goals and tasks are displayed on the same page - goals#index. My issue is that I'm not sure how to get all tasks for a particular goal (that belongs to a user). I understand that I need to pass an ID param to the Goal model in order to find out its tasks, like so:
Goal.find(1).tasks
The above works fine, as I've already set up foreign keys on the tasks table and have a has_many :tasks relationship for the Goal model and a belongs_to relationship for the Task model.
Here's my Goals controller:
def index
#user = current_user
#goals = #user.goals # list all goals for the current user and assign it to the #goals variable.
# Need to find all tasks for each goal ID and assign it to the #tasks variable. Goal ID needs to be supplied here, but it isn't as we're not in show action.
#tasks = Goal.find(1).tasks
As I said, I can find all tasks for a Goal when I manually enter the ID (1 in this example). This works fine in my app, no errors. But obviously I want to supply these IDs dynamically, and I'm just not sure how I get the params in there.
I have tried the below:
#tasks = Goal.find(params[:id]).tasks
and
#tasks = Goal.find(params[:goal_id]).tasks
And I get the "Couldn't find Goal without an ID" error when I try to iterate over #tasks in my view. Which makes sense, as I don't think the goal params are being passed to it as we're not in the Show action.
Surely there must be an easy Rails way?! I'm stumped and don't really know where to look. Thanks for your help and Happy New Year.
You are getting current user's goals, so when you will do this you have one array object. so when you will pass array object to find, it will have multiple IDS. so when need to find All the tasks from all goals you just need to pass Array of IDS instead of single value.
#tasks = Task.where(:goal_id => #goals)
This will run this SQL query.
SELECT "tasks".* FROM "tasks" WHERE "tasks"."goal_id" IN (SELECT
"goals"."id" FROM "goals")
So when you are dealing with array just pass ids. for e.g. [1,2,3]
Once you do #goals = #user.goals (assuming that's working, which it sounds like it is), you have your goals and there is no reason to go back to the DB to "find" them.
To get ALL your tasks from ALL of user's goals, you can do the following:
#tasks = []
#goals.each do |goal|
#tasks << goal.tasks
end
Ah of course, #goals is an array of the user's goals so I can just work with that. So simple when someone just tells you. Thanks for all your help!
Here's my final code that works (I left the controller unchanged). This gets the first goal in the array and then gets the tasks associated with each goal. I have a set number of goals so I can just use goals[0], goals[1] or goals[2] for each goal.
<% #goals[0].tasks.each do |task| %>
<li><div class="task-item"><%= task.task_name %></div></li>
<% end %>
I'm currently using
puts #object.inspect
to debug the results of queries in rails, but the output doesn't seem to include any joins I've defined for the query. How do I get the full array to show?
For example, if I do the following
#object = Object.joins("JOIN associations ON associations.id = object.association_id")
.where(:id => params[:object_id])
.select("objects.*, associations.*")
.first
puts #object.inspect
I get the all the Object fields in my debug array, but none of the association fields. Yet they are there when I try to use them in my view (#object.association_field etc)
PS - the above query looks ugly, I'm only trying to pull one record, but I was getting various errors if I tried to use .find() instead of .where().first. Suggestions welcome on how to make it more railsy
Why not the simplest possible way:
#object = Object.find(params[:object_id])
#association = #object.associations.first
puts "#{#object.inspect}, #{#association.inspect}"
(assuming that has_many :associations is defined in Object)
And the reason you are not getting fields for association is because the only thing that joins does is joining to another table in SQL. It does not fetch joined data. select only select subset of object's attributes, I think the rest is just ignored.
I suspect my question is stupid and answer is obvious, but I TOTALLY stuck with it.
In controller movies_controller.rb I have method index, which fills the array #movies with values from database by calling #movies = Movie.all, and method sort, which do almost the same, but use #movies = Movie.order(:title) instead.
If I call sort explicitly from index what I see in View Index.html.haml is sorted by title list of movies as I expect. But, how can I call method sort by clicking on link? I try
In Index.html.haml:
%th= link_to 'Movies title', 'movies', :on_click => 'self.sort'
In routes.rb:
match ":controller => movies, :action => sort" => 'movies/index'
and nothing is happening, method sort never executes. Actually, I have no idea how to do it right. Looks like it is obvious for everyone, but me.
Can I find short answer how to do it right? Please, kick me in right direction!
If you are looking for sorting data in table then you need some plug in to in place sort the table according to some attribute. following jquery plugin help you to do that,
https://github.com/linjunpop/jquery-tablesorter-rails
or you can achieve the same with background sorting with order clause. check out the following,
http://railscasts.com/episodes/228-sortable-table-columns
For quick and easy you can use 'ransack' gem.
For some writing by yourself check this out http://railscasts.com/episodes/228-sortable-table-columns
So I am trying to find all entries in my table that have a specific value in a particular column. The only way I can think off to do this is to look at each entry and see if it has the value but I was hoping there would be a more efficient solution - this gets unwieldy once you have a sizable database.
Does anyone have a better idea?
Update - I am creating an HTML table and I want to populate the table with all the entries in my model that have a certain value in a particular column. I am trying to do:
<%= render #users.where("column_name = 'value'") %>
as the answer below recommends but I get "undefined method `where' for nil:NilClass" error.
Update 2 - I am not sure why #users would be nil but I will try to figure that out later. For now, I tried
<% #user_message = User.where("column_name = 'value'") %>
<%= render #user_message %>
but it doesn't show any entries at all.
Update 3 - When I do, User.all in rails console, I get all the users so I know the data is there. However, when I do User.where("column_name = 'value'"), I get an empty array. I double checked the column name and value to make sure that the data was present.
Update 4 - Fixed! - I'm not sure why it didn't work in rails console but I got it to work in the site. I called my partial _user_message.html.erb. Apparently it still needs to be called _user.html.erb. Thanks for the help everyone!
Sounds like you want to do a where query, i.e.
#records = Model.where(:some_column => some_value)
Rails has excellent documentation, I suggest you take a look at the ActiveRecord Query guide:
http://guides.rubyonrails.org/active_record_querying.html
ian.
I'm working on implementing a search form in a ruby on rails application. The general idea is to use form_tag to submit the search fields (via params) to a search function in the model of the class I'm trying to search. The search function will then iterate through each of the params and execute a scoping function if the name of the function appears in params.
The issue is that when I call the search on a collection like so:
#calendar.reservations.search({:search_email => "test"})
I don't know how to refer to the collection of #calendar.reservations from within the search function.
Additionally I'm confused as to why #calendar.reservations.search(...) works, but Reservations.all.search gives me an error saying you can't call an instance method on an array.
I've got the details of the search method over here: https://gist.github.com/783964
Any help would be greatly appreciated!
I don't know how to refer to the
collection of #calendar.reservations
from within the search function.
If you use self (or Reservation, it's the same object) inside the classmethod, you will access the records with the current scope, so in your case you will see only the reservations of a particular calendar.
[edit] I looked at you search function, and I think what you want is:
def self.search(search_fields)
search_fields.inject(self) do |scope, (key, value)|
scope.send(key, value)
end
end
Additionally I'm confused as to why
#calendar.reservations.search(...)
works, but Reservations.all.search
gives me an error saying you can't
call an instance method on an array.
#calendar.reservations does not return a standard array but a (lazy) AssociationCollection, where you can still apply scopes (and classmethods as your filter). On the other hand Reservation.all returns a plain array, so you cannot execute search there (or any scope, for that matter).
You don't really need a search method at all, as far as I can tell.
Simply use where:
#calendar.reservations.where(:search_email => 'test')
I would strongly encourage you to look at the MetaSearch GEM by Ernie Miller. It handles the kind of thing you're working on very elegantly and is quite easy to implement. I suspect that your view code would almost accomplish what the GEM needs already, and this would take care of all your model searching needs very nicely.
Take a look and see if it will solve your problem. Good luck!
Reservation.all.search doesn't work because it returns all the results as an array, while Reservation.where(..) returns an ActiveRecord object (AREL). Reservation.all actually fetches the results instead of just building the query further, which methods like where, limit etc do.