Rails show record start from db with specific letters - ruby-on-rails

I want to show only those inquiry processes where company name starts from specific letters. I thought I should use start_with? but in the code below I've an error
NoMethodError (undefined method `start_with?'
def call
InquiryProcess.all.includes(inquiry_field_responses: :inquiry_field).select do |process|
process.inquiry_field_responses.select do |inquiry_field_responses|
inquiry_field_responses.inquiry_field.name == 'company_name'
end&.last&.value == start_with?('aaa')
end
end

I would do something like this:
field = InquiryField.find_by!(name: 'company_name')
response_table = InquiryFieldResponse.arel_table
responses = field.inquiry_field_responses.where(response_table[:value].matches('aaa%'))
processes = InquiryProcess.where(id: responses.select(:inquiry_process_id))
First select the field that you want to check the values of. From there select all responses that belong to that specific field and start with 'aaa'. Then select the processes using the responses.
The issue with your current code is that you'll do:
'some string' == start_with?('aaa')
Which should be:
'some string'.start_with?('aaa')
Or more specific to your case:
end.last&.value&.start_with?('aaa')

It's much more easier.
Just use SQL for this:
InquiryProcess.where("company_name LIKE ?", "aaa%")
This shows you all inquiry_processes that company_name starts with aaa

Related

How does one get the "next" record from database sorted by a specific attribute without loading all the records?

Here's the situation:
I have an Event model and I want to add prev / next buttons to a view to get the next event, but sorted by the event start datetime, not the ID/created_at.
So the events are created in the order that start, so I can compare IDs or get the next highest ID or anything like that. E.g. Event ID 2 starts before Event ID 3. So Event.next(3) should return Event ID 2.
At first I was passing the start datetime as a param and getting the next one, but this failed when there were 2 events with the same start. The param start datetime doesn't include microseconds, so what would happen is something like this:
order("start > ?",current_start).first
would keep returning the same event over and over because current_start wouldn't include microseconds, so the current event would technically be > than current_start by 0.000000124 seconds or something like that.
The way I got to work for everything was with a concern like this:
module PrevNext
extend ActiveSupport::Concern
module ClassMethods
def next(id)
find_by(id: chron_ids[current_index(id)+1])
end
def prev(id)
find_by(id: chron_ids[current_index(id)-1])
end
def chron_ids
#chron_ids ||= order("#{order_by_attr} ASC").ids
end
def current_index(id)
chron_ids.find_index(id)
end
def order_by_attr
#order_by_attr ||= 'created_at'
end
end
end
Model:
class Event < ActiveRecord::Base
...
include PrevNext
def self.order_by_attr
#order_by_attr ||= "start_datetime"
end
...
end
I know pulling all the IDs into an array is bad and dumb* but i don't know how to
Get a list of the records in the order I want
Jump to a specific record in that list (current event)
and then get the next record
...all in one ActiveRecord query. (Using Rails 4 w/ PostgreSQL)
*This table will likely never have more than 10k records, so it's not catastrophically bad and dumb.
The best I could manage was to pull out only the IDs in order and then memoize them.
Ideally, i'd like to do this by just passing the Event ID, rather than a start date params, since it's passed via GET param, so the less URL encoding and decoding the better.
There has to be a better way to do this. I posted it on Reddit as well, but the only suggested response didn't actually work.
Reddit Link
Any help or insight is appreciated. Thanks!
You can get the next n records by using the SQL OFFSET keyword:
china = Country.order(:population).first
india = City.order(:population).offset(1).take
# SELECT * FROM countries ORDER BY population LIMIT 1 OFFSET 1
Which is how pagination for example often is done:
#countries = Country.order(:population).limit(50)
#countries = scope.offset( params[:page].to_i * 50 ) if params[:page]
Another way to do this is by using would be query cursors. However ActiveRecord does not support this and it building a generally reusable solution would be quite a task and may not be very useful in the end.

dynamic query for different values rails 4 activerecord

Here is the query I am trying in my controller
query = []
if id
query = "category_id: #{id}"
end
#posts = Post.where(query)
But throwing error as ERROR: syntax error at or near ":"
Why this is not working any other way to do it
if id
query << {sub_category_id: id}
end
if test
query << {test_id: test}
end
#posts = Post.where(query)
Is there any way of doing like this
Change query to a hash instead of string:
if id
query = { category_id: id }
end
#posts = Post.where(query)
The reason query = "category_id: #{id}" did not work is because the supplied string is literally used in the query generated by ActiveRecord, i.e. your select query will have category_id: 1 (assuming id is 1) in the where clause. And this is not a valid SQL syntax.
Please read on how you can use strings in conditions following this link. Thanks to #RustyToms for suggesting the link.
Update: ( Add extra conditions to the query hash )
if id
query[:sub_category_id] = id
end
if test
query[:test_id] = test
end
#posts = Post.where(query)
Another way to do this:
#posts = Post.scoped
#posts = #posts.where(category_id: id) if id
(in case you're playing codegolf)
Edit: (this is definitely a side note that isn't at all relevant)
Your original solution relies on one of my least favorite features of Ruby. Consider the following code:
if false
a = 4
end
puts a
I would expect the puts a to fail with a NameError (undefined local variable "a"), but no! The Ruby parser hits a = and then initalizes its value to nil. So, despite the fact that there is no way for the innards of that if statement to run, it still impacts the other code.

How can I limit an existing Rails AR query by a certain time frame?

I have a dashboard(esque) view in a Rails app which is showing some data in similar ways but broken out into many time periods.
I have some code in my controller like so:
#issues_this_month = Issue.where('issues.created_at BETWEEN ? AND ?', DateTime.now.in_time_zone.beginning_of_month, DateTime.now.in_time_zone.end_of_month)
and I also want to create a variables which shows issues this year and issues all time so I have this code:
#issues_this_year = Issue.where('issues.created_at BETWEEN ? AND ?', DateTime.now.in_time_zone.beginning_of_year, DateTime.now.in_time_zone.end_of_year)
I am curious if someone can think of a good way of doing one query, and from that inferring the date ranges all while avoiding the extra queries. Should I pass the results to a helper method and do the logic there?
in the model... you can define
def date
self.created_at.to_date
end
then in the controller
start = Date.today.beginning_of_year
end = Date.today.end_of_year
#issues_this_year = Issue.where(create_at: start..end).group_by(&:date)
now you have a hash of [month_1, {issues that exist in month_1}, month_2, {issues that exist in month_2}, etc]. play with it in the console to find the proper keys... #issues_this_year.keys
How about defining a method like
def self.in_timeframe(start_time=DateTime.now.in_time_zone.beginning_of_month,
end_time=DateTime.now.in_time_zone.end_of_month)
Issue.where('issues.created_at BETWEEN ? AND ?', start_time, end_time)
end
You can now invoke this as follows:
Issue.in_timeframe # For issues in the month
Issue.in_timeframe(x,y) # For issues within x-y timeframe
If you want the data in a single query, you could do stuff like:
def self.in_timeframes(time_frames)
data = {}
times_frames.each do |time_frame|
data[time_frame[:name]] = Issue.in_timeframe(time_frame[:srtart]. time_frame[:end])
end
data
end
You can invoke the above method using:
time_frames = [{:name=>"month"},
{:name=>"x-y", :start=>x, :end=>y}]
Issue.in_timeframes(time_frames)

Rail3 'Return False Unless XYZ' Query Not Working

In my rails3.1 application, I'm trying to apply the following logic in one of my order model.
def digital?
line_items.map { |line_item| return false unless line_item.variant_id = '102586070' }
end
I've created a separate variant called prepaid_voucher which has id = 102586070. Despite this, the result is false...
Order has many line_items
LineItem belongs to order and variant
Variant has many line_items
Is this the best way to perform such a task and how can I fix?
First of all I think you want a double == here line_item.variant_id = '102586070', then I rather go for something like that (If I understand what you want)
def digital?
line_items.select{|line_item| line_item.variant_id == '102586070'}.any?
end
But it's hard to understand what you really want, what is the expected behavior if the id is not found?

Rails - Conditional Query, with ActiveRecord?

Given a query like:
current_user.conversations.where("params[:projectid] = ?", projectid).limit(10).find(:all)
params[:projectid] is being sent from jQuery ajax. Sometimes that is an integer and the above works fine. But if the use selects "All Projects, that's a value of '' which rails turns into 0. which yields an invalid query
How with rails do you say search params[:projectid] = ? if defined?
Thanks
I think you may have mistyped the query a bit. "params[:projectid] = ?" shouldn't be a valid query condition under any circumstances.
In any case, you could do some sort of conditional statement:
if params[:project_id].blank?
#conversations = current_user.conversations.limit(10)
else
#conversations = current_user.conversations.where("project_id = ?", params[:project_id]).limit(10)
end
Although, I'd probably prefer something like this:
#conversations = current_user.conversations.limit(10)
#converstaions.where("project_id = ?", params[:project_id]) unless params[:project_id].blank?
Sidenotes:
You don't have to use .find(:all). Rails will automatically execute the query when the resultset is required (such as when you do #conversations.each).
Wherever possible, try to adhere to Rails' snakecasing naming scheme (eg. project_id as opposed to projectid). You'll save yourself and collaborators a lot of headaches in the long run.
Thanks but if the where query has lets say 3 params, project_id, project_status, ... for example, then the unless idea won't work. I'm shocked that Rails doesn't have a better way to handle conditional query params
EDIT: If you have multiple params that could be a part of the query, consider the fact that where takes a hash as its argument. With that, you can easily build a parameter hash dynamically, and pass it to where. Something like this, maybe:
conditions = [:project_id, :project_status, :something_else].inject({}) do |hsh, field|
hsh[field] = params[field] unless params[field].blank?
hsh
end
#conversations = current_user.conversations.where(conditions).limit(10)
In the above case, you'd loop over all fields in the array, and add each one of them to the resulting hash unless it's blank. Then, you pass the hash to the where function, and everything's fine and dandy.
I didn't understand why you put:
where("params[:projectid] = ?", projectid)
if you receive params[:project] from the ajax request, the query string shouldn't be:
where("projectid = ?", params[:projectid])
intead?
And if you are receiving an empty string ('') as the parameter you can always test for:
unless params[:projectid].blank?
I don't think i undestood your question, but i hope this helps.

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