I know there is a simple answer to this question but I have searched for 2 days trying to find it. I have a program in rails that lists workers in the home building industry. I ask for the following informatio occupation, first name, second name,telephone number, email address. This information is displayed without any editing of my code. I would like to display this information using the order query and showing the information using the occupation column in descending order. Please tell me the code to use and where it goes.
I assume you have a method named index inside your controller. Ok, inside the index method, you can use .order method.
Make it like this:
def index
#users = User.order(occupation: :desc)
end
Reference:
http://apidock.com/rails/ActiveRecord/QueryMethods/order
Related
In my rails app I have defined in the Kid model a calculation based on the fields from the Kids DB. the method is as follows:
def flip_date
self.dob.advance(months: 10)
end
I want to use this in my controller as I have a method where I am defining something as follows:
new_kids = Kid.where(discharge_date: nil).where('flip_date > ?', Date.current.advance(year: 1).beginning_of_year)
However I keep getting the following error:
SQLite3::SQLException: no such column: flip_date: SELECT "kids".* FROM "kids" WHERE "kids"."discharge_date" IS NULL AND (flip_date < '2017-01-01')
Any ideas on how can I make this work? All help is appreciated!
If you really want to use model methods take a look at http://apidock.com/rails/v4.0.2/ActiveRecord/QueryMethods/select
For your case:
new_kids = Kid.where(discharge_date: nil).select{|k| k.flip_date > Date.current.advance(year: 1).beginning_of_year}
But select method takes every object in memory before returning final result. Hence I will advise to use normal where clause and instead of flip_date take dob (which is a column in database) in consideration.
Like this
new_kids = Kid.where(discharge_date: nil).where('dob > ?', <date criteria>)
The select method (http://apidock.com/rails/v4.0.2/ActiveRecord/QueryMethods/select) works great if you are okay with the return being an Array.
I am still looking for a way to do this with an ActiveRecord_Relation return.
If others know how to do this, it would be much appreciated if you can share.
This example doesn't respond to your specific code, but to the extent it helps someone else with a similar question, here's a very simple example of how .select can be really handy:
#expired_memberships = User.select{|u| u.membership_expired_yesterday?}
In that example you've looped through all your Users and filtered them based on a custom method you defined on the User model (membership_expired_yesterday?). Now you can easily do stuff with that collection like this example in a mailer:
#expirations.each do |user|
MembershipExpirationMailer.with(user: user).first_reminder.deliver_now
end
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 want to count the number of visits on my blog? Can someone please suggest the overall method to implement this feature?
It is just an idea. You can add a count_view column in the database into blogs table with default value 0.
And in the show action of BlogsController add the following code
def show
#blog = Blog.where('id = ?', params[:id]).first
#blog.update_column('count_view', #blog.count_view + 1) if #blog.present?
end
You can modify this logic as per your requirement.
You can check the hit counter gem or the impressionist gem.
You could also use an existing (free) analytics solutions if you want to get much more data than the number of times the action was called (please note that if the same user refreshes the browser 5 times, you get 5 hits):
http://www.google.com/analytics/
Using these you can get data like unique visitors, referral URL, locations data, browser, OS, and a lot of different stuff to make informed decisions. There are several other options (paid, free, real time) available as well:
https://mixpanel.com
https://www.kissmetrics.com/
I'm building a sort-of Twitter clone, with (amongst others), models and Hashtag and Post, which have a has_many: through: relationship with each other.
Currently, visiting /hashtags/pizza will take you to a page that shows all posts with hashtag the hashtag #pizza. I want to add functionality so you can pass multiple hashtags in a URL and see the posts which contain all of those hashtags. For example, if you visited /hashtags/pizza/pasta (or hashtags/?pizza&pasta' or whatever's easiest to implement) you'd be shown a page containing all Posts which have BOTH the hashtag #pizza and the hashtag #pasta.
How would I do this? I have no idea where to begin.
For the record, my imagined code in the controller would be something like this. Feel free to poke holes in it:
1 def show
2 requested_hashtags = ??????? # an array of hashtags e.g. ["music", "guitar"]
3 hashtag1 = Hashtag.find_by_name(requested_hashtags[0]) # in this case r_h[0] = music
4 hashtag2 = Hashtag.find_by_name(requested_hashtags[1]) # and r_h[1] = guitar
5 #posts = hashtag1.posts & hashtag2.posts
6 end
Then in my view I'd just iterate over #posts. (The above example is dumbed down in that it assumes there's always exactly two hashtags requested but the principle is the same.)
So my question is, how do I complete line 2 of the code snippet above?
You can treat the url like any other string, so you could create a url like:
hashtags/?tags=pizza,pasta
And then in your controller (line 2):
requested_hashtags = params[:tags].split(",")
Another more commonly used approach in Rails is:
hashtags/?tags[]=pizza&tags[]=pasta
and then in your controller:
requested_hashtags = params[:tags]
This second way is a pretty standard Rails convention.
I am new in this world of Rails. And I cannot get my head around this problem. How to get #microposts ordered by the date the micropost was created.
This is the line
#microposts = current_user.followeds.map(&:microposts).flatten
I only managed to order by date the 'followeds', but that is not what I am looking for. All the attempts I have made gave me errors, so I guess I am not aware of some syntax.
Any help is welcome!
Normally, you would add an order clause, as in:
Micropost.where(:written_by => current_user.followeds).order(:created_at)
The way you currently have this line structured doesn't permit that, however, since order is only available on ActiveRecord::Relations, and once you do map you no longer have a Relation available to chain on.
If that's the case, you'll want something like:
current_user.followeds.map(&:microposts).flatten.sort_by { |m| m.created_at }
I think you should try to approach this from another angle.
How about something like this:
#microposts = Micropost.where(author_id: current_user.followed_ids).order(:created_at).all
You might of course have to exchange author_id for whatever foreign key you have to identify what user a Micropost was written by.
If you want to reverse the posts (newest first), you just write order("created_at desc") instead.