What is the effective way of this code?I think there should be better way.I wanna re-code this.
if #project.contest_entries.where("view_in_showcase = ?", true)
entries = #project.contest_entries.where("view_in_showcase = ?", true).count
else
entries = 1
end
You could use max:
entries = [1, #project.contest_entries.where(view_in_showcase: true).count].max
I would define a scope on ContestEntry to get rid of that where clause though:
scope :showcased, where(view_in_showcase: true)
Then that would become
entries = [1, #project.contest_entries.showcased.count].max
showcased_project_entries =
#project.contest_entries.where("view_in_showcase = ?", true)
entries = showcased_project_entries ? showcased_project_entries.count : 1
or
entries =
#project.contest_entries.where("view_in_showcase = ?", true).try(:count) || 1
Although, I must admit I am not sure under which circumstances where returns a falsy value.
EDIT: As noted in the comments, the else clause indeed never triggers, so your code probably does not do what you want. See Andy H's solution for the case where you want to have entries be 1 when you find no results, if that is what you meant.
Related
I have a dashboard that allows for filtering of the results by different parameters. I build methods to filter the results by the given criteria. One area where I'm having trouble is if the previous line should null out the active record relation. Should I just put a bunch of if present? stat
def find_website_stats(options = {})
if options[:date_between].present?
start_date = options[:date_between].split(/-/).first.to_date
end_date = options[:date_between].split(/-/).last.to_date + 1
elsif options[:start_date].present?
start_date = options[:start_date].to_date
end_date = options[:end_date].to_date + 1 if options[:end_date].present?
end
contractor_name = options[:search_contractor] if options[:search_contractor].present?
distributor_name = options[:search_distributor] if options[:search_distributor].present?
distributor_ids = options[:with_distributor] if options[:with_distributor].present?
contractor_ids = options[:with_contractor] if options[:with_contractor].present?
with_country = options[:with_country] if options[:with_country].present?
with_state = options[:with_state] if options[:with_state].present?
search_city = options[:search_city] if options[:search_city].present?
web_stats = self.website_stats
if web_stats.present?
web_stats = web_stats.where(contractor_id: [*contractor_ids]) if contractor_ids.present?
if distributor_ids.present?
web_stat_ids = DistributorWebsiteStat.where(distributor_id: [*distributor_ids]).pluck(:website_stat_id)
web_stats = web_stats.where(id: [*web_stat_ids])
end
web_stats = web_stats.where(date_recorded: start_date..end_date) if start_date.present? && end_date.present?
web_stats = web_stats.with_country(with_country) if with_country.present?
web_stats = web_stats.with_state(with_state) if with_state.present?
web_stats = web_stats.search_city(search_city) if search_city.present?
#untested
if contractor_name.present?
searched_contractor_ids = Brand.search_contractor(contractor_name).pluck(:id)
web_stats = web_stats.where(contractor_id: [*searched_contractor_ids])
end
if distributor_name.present?
searched_distributor_ids = Brand.search_distributor(distributor_name).pluck(:id)
web_stat_ids = DistributorWebsiteStat.where(distributor_id: [*searched_distributor_ids])
web_stats = web_stats.where(id: [*web_stat_ids])
end
#end untested
end
web_stats
end
Where I'm specifically having a problem right now is the line that says if web_stat_ids.present?
So at first I grab all the website stats this object is associated with and then look to see if there are any for the given distributor.
If there is none for the given distributor web_stat_ids obviously returns nil
Then when I go to the line web_stats.where(id: [*web_stat_ids]) that's obviously going to return the same thing that I had before, rather than an empty active record relation, which is what I need it to be?
If I make this an empty array the next few statements with "where" won't work because it's an array and not an active record relation.
I know I can wrap this stuff in a bunch of if present? && statements...but I was wondering if there is a better solution to my problem?
In case anyone else is looking for this, found the answer from this SO post: How to return an empty ActiveRecord relation?
Model.none rails 4+
I have two queries, I need an or between them, i.e. I want results that are returned by either the first or the second query.
First query is a simple where() which gets all available items.
#items = #items.where(available: true)
Second includes a join() and gives the current user's items.
#items =
#items
.joins(:orders)
.where(orders: { user_id: current_user.id})
I tried to combine these with Rails' or() method in various forms, including:
#items =
#items
.joins(:orders)
.where(orders: { user_id: current_user.id})
.or(
#items
.joins(:orders)
.where(available: true)
)
But I keep running into this error and I'm not sure how to fix it.
Relation passed to #or must be structurally compatible. Incompatible values: [:references]
There is a known issue about it on Github.
According to this comment you might want to override the structurally_incompatible_values_for_or to overcome the issue:
def structurally_incompatible_values_for_or(other)
Relation::SINGLE_VALUE_METHODS.reject { |m| send("#{m}_value") == other.send("#{m}_value") } +
(Relation::MULTI_VALUE_METHODS - [:eager_load, :references, :extending]).reject { |m| send("#{m}_values") == other.send("#{m}_values") } +
(Relation::CLAUSE_METHODS - [:having, :where]).reject { |m| send("#{m}_clause") == other.send("#{m}_clause") }
end
Also there is always an option to use SQL:
#items
.joins(:orders)
.where("orders.user_id = ? OR items.available = true", current_user.id)
You can write the query in this good old way to avoid error
#items = #items.joins(:orders).where("items.available = ? OR orders.user_id = ?", true, current_user.id)
Hope that helps!
Hacky workaround: do all your .joins after the .or. This hides the offending .joins from the checker. That is, convert the code in the original question to...
#items =
#items
.where(orders: { user_id: current_user.id})
.or(
#items
.where(available: true)
)
.joins(:orders) # sneaky, but works! 😈
More generally, the following two lines will both fail
A.joins(:b).where(bs: b_query).or(A.where(query)) # error! 😞
A.where(query).or(A.joins(:b).where(bs: b_query)) # error! 😞
but rearrange as follows, and you can evade the checker:
A.where(query).or(A.where(bs: b_query)).joins(:b) # works 😈
This works because all the checking happens inside the .or() method. It's blissfully unaware of shennanigans on its downstream results.
One downside of course is it doesn't read as nicely.
I ran into the same issue, however the code was defined in a different place and was very difficult to change directly.
# I can't change "p"
p = Post.where('1 = 1').distinct # this could also be a join
And I needed to add an or statement to it
p.or(Post.where('2 = 2'))
The following code won't raise an error, because it has distinct like the initial relationship.
p.or(Post.where('2 = 2').distinct)
The problem with it it that it only works as long as you know the relationship. It may or not have a join, or distinct.
This works regardless of what the relationship is:
p.or(p.unscope(:where).where('2 = 2'))
=> SELECT DISTINCT `posts`.* FROM `posts` WHERE ((1 = 1) OR (2 = 2))
It occurs when you try to combine two multi-active records of the same type, but one of them has a joins value or an includes value, or in your case a reference value, that the other does not.
Therefore we need to match the values between them, and I found a general way to do this without knowing the actual values in advance.
items_1 = #items.joins(:orders)
.where(orders: { user_id: current_user.id})
items_2 = #items.where(available: true)
.joins(items_1.joins_values)
.includes(items_1.includes_values)
.references(items_1.references_values)
#items = items_1.or(items_2)
just solve it!
def exec_or_statement(q1, q2)
klass = q1.klass
key = klass.primary_key
query_wrapper_1 = {}
query_wrapper_1[key] = q1
query_wrapper_2 = {}
query_wrapper_2[key] = q2
klass.where(query_wrapper_1).or(klass.where(query_wrapper_2))
end
query_1 = #items.where(available: true)
query_2 =
#items
.joins(:orders)
.where(orders: { user_id: current_user.id})
exec_or_statement(query_1, query_2)
Assume I have an arbitrary number of Group records and I wanna query User record which has_many :groups, the catch is that users are queries by two bound fields from the groups table.
At the SQL level, I should end up with something like this:
SELECT * FROM users where (categories.id = 1 OR users.status = 0) OR(categories.id = 2 OR users.status = 1) ... -- to infinity
This is an example of what I came up with:
# Doesn't look like a good solution. Just for illustration.
or_query = groups.map do |g|
"(categories.id = #{g.category.id} AND users.status = #{g.user_status.id} )"
end.join('OR')
User.joins(:categories).where(or_query) # Works
What I think I should be doing is something along the lines of this:
# Better?
or_query = groups.map do |g|
"(categories.id = ? AND users.status = ? )".bind(g.category.id, g.user_status.id) #Fake method BTW
end.join('OR')
User.joins(:categories).where(or_query) # Works
How can I achieve this?
There has to be a better way, right?
I'm using Rails 4.2. So the shiny #or operator isn't supported for me.
I would collect the condition parameters separately into an array and pass that array (splatted, i.e. as an arguments list) to the where condition:
or_query_params = []
or_query = groups.map do |g|
or_query_params += [g.category_id, g.user_status.id]
"(categories.id = ? AND users.status = ?)"
end.join(' OR ')
User.joins(:categories).where(or_query, *or_query_params)
Alternatively, you might use ActiveRecord sanitization:
or_query = groups.map do |g|
"(categories.id = #{ActiveRecord::Base.sanitize(g.category_id)} AND users.status = #{ActiveRecord::Base.sanitize(g.user_status.id)})"
end.join(' OR ')
User.joins(:categories).where(or_query)
I'm writing a forum application in Rails and I'm stuck on limiting nested quotes.
I'm try to use regex and recursion, going down to each matching tag, counting the levels and if the current level is > max, deleting everything inside of it. Problem is that my regex is only matching the first [ quote ] with the first seen [ /quote ], and not the last as intended.
The regex is just a slight tweak of what was given in the docs of the custom bbcode library I'm using (I know very little about regex, I've tried to learn as much as I can in the past couple days but I'm still stuck). I changed it so it'd include [quote], [quote=name] and [quote=name;222] . Could someone examine my code and let me know what the problem could be? I'd appreciate it lots.
def remove_nested_quotes(post_string, max_quotes, count)
result = post_string.match(/\[quote(:.*)?(?:)?(.*?)(?:)?\](.*?)\[\/quote\1?\]/mi)
if result.nil?
return false
elsif (count = count+1) > max_quotes
full_str = result[0]
offset_beg = result.begin(3)
offset_end = result.end(3)
excess_quotes = full_str[offset_beg ..offset_end ]
new_string = full_str.slice(excess_quotes )
return new_string
else
offset_beg = result.begin(3)
offset_end = result.end(3)
full_str = result[0]
inner_string = full_str[offset_beg..offset_end]
return remove_nested_quotes(inner_string , max, count)
end
end
I mean something like
counter = 0
max = 5
loop do
matched = false
string.match /endquote|quote/ do |match|
matched = true
if endquote matched
counter -= 1
else # quote matched
counter += 1
end
if counter > max
# Do something, break or return
else
string = match.post_match
end
end
break unless matched
end
This must be a basic thing in rails, but I don't know how to do it.
I would like to filter participants based on the languages they speak. People can speak multiple languages, and languages are stored in their own table with a one-to-many relationship.
Now my search looks really clunky and doesn't seem to work:
if #cvsearch.language.present? == true and #cvsearch.language != 0
#p = #p.joins(:languages).where('languages.name = ?', #cvsearch.language)
else
#cvsearch.language = 0
end
if #cvsearch.language1.present? == true and #cvsearch.language1 != 0
#p = #p.joins(:languages).where('languages.name = ?', #cvsearch.language1)
end
if #cvsearch.language2.present? == true and #cvsearch.language2 != 0
#p = #p.joins(:languages).where('languages.name = ?', #cvsearch.language2)
end
if #cvsearch.language3.present? == true and #cvsearch.language3 != 0
#p = #p.joins(:languages).where('languages.name = ?', #cvsearch.language3)
end
The resulting SQL, slightly shortened:
SELECT COUNT(*) FROM "participants" INNER JOIN "languages" ON "languages"."participant_id" = "participants"."id" WHERE (participants.id >= 2) AND (languages.name = 11) AND (languages.name = 10)[0m
It would be great to get a specific solution, but even better is a pointer as to where I can read up on this - what's the key word I am missing to describe this problem?
So this is the solution I am using for now:
if #cvsearch.language1.present? == true and #cvsearch.language1 != 0
safe_lang = ActiveRecord::Base::sanitize(#cvsearch.language1)
qry = "INNER JOIN languages l1 ON l1.participant_id = participants.id AND l1.name = " + safe_lang.to_s
#p = #p.joins(qry)
end
Works wonderfully, just need to get some feedback regarding the safety of this approach.
I'm not sure of a general reference to refer you to, but this is basic SQL stuff. Basically, the JOIN is performed first resulting in a number of rows and then the WHERE is applied, filtering the rows. The conceptual mistake here is thinking that the WHERE clause will somehow apply to the full set of matched languages, but it doesn't work that way, each row of the result is considered in isolation, therefore a clause like (languages.name = 11) AND (languages.name = 10) will never return anything, because languages.name only has a single value in each row. The query as constructed could only work for an OR clause, so you could say something like WHERE (languages.name = 11) OR (languages.name = 12).
In order to filter down the participants you need one join for each language, so you want something like this:
SELECT COUNT(*) FROM participants
INNER JOIN languages l1 ON l1.participant_id = participants.id AND (languages.name = 10)
INNER JOIN languages l2 ON l2.participant_id = participants.id AND (languages.name = 11)
WHERE participants.id >= 2
Offhand I'm not sure of the easiest way to do this in ActiveRecord, it's not a super common query. Your general structure should work, but with something like:
if #cvsearch.language1.present? == true and #cvsearch.language1 != 0
safe_language = ActiveRecord::Base.sanitize(#cvssearch.language1)
join_clause = "INNER JOIN languages l1 ON l1.participant_id = participants.id AND language.name = #{safe_language}"
#p = #p.joins(join_clause)
end