When using Rails with ActiveRecord (and PostgreSQL), executing "simple" queries adds a name to them, e.g. calling
Article.all
# => Article Load (2.6ms) SELECT "articles".* FROM "articles"
names the query Article Load. However, when executing slightly more complex queries, no name is being generated, as for example with
Article.group(:article_group_id).count
# => (1.2ms) SELECT COUNT(*) AS count_all, "articles"."article_group_id" AS articles_article_group_id FROM "articles" GROUP BY "articles"."article_group_id"
I can add a name if executing a custom query using the execute method:
ActiveRecord::Base.connection.execute("SELECT * FROM articles", "My custom query name")
# => My custom query name (2.5ms) SELECT * FROM articles
But is there a way to add a custom name to a query built with the ActiveRecord-methods?
If you wonder why: The name is useful for all kinds of monitoring, e.g. when looking at slow queries in AppSignal.
Since you just want to custom query name for monitoring purpose, so i think you only need to change the query name in the ActiveRecord::ConnectionAdapters#log method, this method is the one log the sql query that be executed, include the query name.
Here is my solution:
# lib/active_record/base.rb
# note that MUST be base.rb
# otherwise you need to add initializer to extend Rails core
#
module ActiveRecord
module ConnectionAdapters
class AbstractAdapter
attr_accessor :log_tag
private
alias old_log log
def log(sql, name = "SQL", binds = [], type_casted_binds = [], statement_name = nil)
if name != 'SCHEMA'
name = #log_tag
#log_tag = nil # reset
end
old_log(sql, name, binds, type_casted_binds, statement_name) do
yield
end
end
end
end
module QueryMethods
def log_tag(tag_name) # class method
spawn.log_tag(tag_name)
self
end
end
module Querying
delegate :log_tag, to: :all
end
class Relation
def log_tag(tag_name) # instance method
conn = klass.connection
conn.log_tag = tag_name
self
end
end
end
Demo
Task.log_tag("DEMO").group(:status).count
# DEMO (0.7ms) SELECT COUNT(*) AS count_all, "tasks"."status" AS tasks_status FROM "tasks" GROUP BY "tasks"."status"
Task.where(status: 6).log_tag("SIX").first(20)
# SIX (0.8ms) SELECT "tasks".* FROM "tasks" WHERE "tasks"."status" = ? ORDER BY "tasks"."id" ASC LIMIT ?
Task.where(status: 6).first(20)
# (0.8ms) SELECT "tasks".* FROM "tasks" WHERE "tasks"."status" = ? ORDER BY "tasks"."id" ASC LIMIT ?
Note
In case you want to fix query name for specific query, you can use a hash with key is the whole the specific sql string (or hash of whole sql, such as the way Rails core cache query: query_signature = ActiveSupport::Digest.hexdigest(to_sql)) and the value is the query name you want.
# set up before hand
ActiveRecord::ConnectionAdapters::LogTags[Product.where...to_sql] = "DEMO"
# AbstractAdapter
LogTags = Hash.new
def log(sql, name...)
name = LogTags[sql]
# ...
end
I am trying to assign a variable tagcolor only if it already exists in the database. This code queries the DB twice if the color is present, once to determine if it does indeed exist and another to actually assign it.
If it doesn't exist I just want to assign tagcolor to the user provided color.
if Tagmap.where("name = ? AND user_id = ?", tag, current_user.id).first.present?
tagcolor = Tagmap.where("name = ? AND user_id = ?", tag, current_user.id).first.color
else
tagcolor = params[:color].downcase
end
Can I reduce this block so I just query the DB once?
Provided you're on Rails 4, you can do:
tagcolor = Tagmap.find_by(name: tag, user: current_user).try(:color) || params[:color].downcase
Similar (but not that pretty) construction is possible in Rails 3:
tagcolor = Tagmap.find_by_name_and_user(tag, current_user).try(:color) || params[:color].downcase
I have a report with a table in Rails where users can optionally set filters like selecting a location or picking a range of dates and update the table via an ajax request.
Can I write this where clause so that it any date/blanks or all locations?
#orders = Order.where('created_at <= ? AND ? <= created_at AND location_id = ?', date_order_start, date_order_end, loc_filter)
The query above fails on blanks (e.g., "") and if I put nils they translate to nulls in the SQL.
To solve this problem right now I have a bunch of conditional statements that check whether value is present in the ajax request and then creates a different where clause depending on the case. My current conditionals are unwieldy, error prone and not scalable.
Searches on things like "wildcard sql" end up leading me to text searches (i.e., %) which I don't think fits in this case.
I am running on Rails 3.2 with postgresql.
I sometimes use an array of query statements and arguments like this:
queries = []
args = []
if some_condition
queries.push("created_at <= ?")
args.push(whatever_date)
end
if another_condition
queries.push("created_at >= ?")
args.push(another_date)
end
#order = Order.where(queries.join(" AND "), *args)
Im trying to build advanced search finder for my Candidate model.
Lets imagine it has couple fields + multiple associations like has_many: languages & has_many: skills. Now I'm building query like this:
query = Candidate.select("*")
if position_name
query = query.where('position_name LIKE ? OR position_name IS NULL',"%#{position_name}%")
end
if salary
query = query.where('salary <= ? OR salary IS NULL',salary)
end
and so on...
Now I want to add more advanced conditions like to find users who only have such skills like PHP and Java (so return only those users who have both skills)
This works but only when I insert OR
query = query.joins(:skills)
query = query.where('`skills`.`name` = ? OR `skills`.`name` = ?',"Java","PHP")
Additionally I'd like the same also for languages (plus, language have language.name & language.level)
Can someone points me in which direction to look? And also how to build such condition where I can multiple skills or multiple languages?
Have a look at the various search gems like Ransack, Metawhere or Searchlogic
http://rubygems.org/gems/ransack
https://github.com/railsdog/searchlogic
Both Ransack and Searchlogic allow searching on associated models and you can use scopes to restrict the search parameters.
Example Search params for Searchlogic.
[search][admitted_gte]
[search][admitted_lte]
[search][aetiology_like_any][] VIRUS
[search][at_risk_gte]
[search][at_risk_lte]
[search][died_gte]
[search][died_lte]
[search][gezi_reference_like]
[search][id]
[search][incidents_location_encrypted_postcode_like]
[search][lab_confirmed_gte]
[search][lab_confirmed_lte]
[search][onset_first_after]
[search][onset_first_before]
[search][onset_last_after]
[search][onset_last_before]
[search][outbreak_type_equals_any][] FOODBORNE
[search][point_source_date_after]
[search][point_source_date_before]
[search][total_affected_gte]
[search][total_affected_lte]
[search][user_reference_like]
[search][year_equals_any][] 2010
search[order] descend_by_id
Outbreak_Controller.rb Index action returns the results of the Search query. From 17 Search params only a single searchlogic call is required #search = Outbreak.search(params[:search]). The params are whitelisted against a list of allowed search params - code not shown.
def index
#set the default index order to be descending Outbreak id
if !params[:search][:order]
params[:search][:order] = "descend_by_id"
end
if params[:search][:bacterial_agents_bacterium_name_like_any] != nil && !params[:search][:bacterial_agents_bacterium_name_like_any].empty?
params[:search][:bacterial_agents_category_like] = "CAUSATIVE"
end
if params[:search][:viral_agents_virus_name_like_any] != nil && !params[:search][:viral_agents_virus_name_like_any].empty?
params[:search][:viral_agents_category_like] = "CAUSATIVE"
end
if params[:search][:protozoal_agents_protozoa_name_like_any] != nil && !params[:search][:protozoal_agents_protozoa_name_like_any].empty?
params[:search][:protozoal_agents_category_like] = "CAUSATIVE"
end
if params[:search][:toxic_agents_toxin_name_like_any] != nil && !params[:search][:toxic_agents_toxin_name_like_any].empty?
params[:search][:toxic_agents_category_like] = "CAUSATIVE"
end
#Outbreak.search takes all of the given params and runs it against the Outbreak model and it's associated models
#search = Outbreak.search(params[:search])
end
Per section 2.2 of rails guide on Active Record query interface here:
which seems to indicate that I can pass a string specifying the condition(s), then an array of values that should be substituted at some point while the arel is being built. So I've got a statement that generates my conditions string, which can be a varying number of attributes chained together with either AND or OR between them, and I pass in an array as the second arg to the where method, and I get:
ActiveRecord::PreparedStatementInvalid: wrong number of bind variables (1 for 5)
which leads me to believe I'm doing this incorrectly. However, I'm not finding anything on how to do it correctly. To restate the problem another way, I need to pass in a string to the where method such as "table.attribute = ? AND table.attribute1 = ? OR table.attribute1 = ?" with an unknown number of these conditions anded or ored together, and then pass something, what I thought would be an array as the second argument that would be used to substitute the values in the first argument conditions string. Is this the correct approach, or, I'm just missing some other huge concept somewhere and I'm coming at this all wrong? I'd think that somehow, this has to be possible, short of just generating a raw sql string.
This is actually pretty simple:
Model.where(attribute: [value1,value2])
Sounds like you're doing something like this:
Model.where("attribute = ? OR attribute2 = ?", [value, value])
Whereas you need to do this:
# notice the lack of an array as the last argument
Model.where("attribute = ? OR attribute2 = ?", value, value)
Have a look at http://guides.rubyonrails.org/active_record_querying.html#array-conditions for more details on how this works.
Instead of passing the same parameter multiple times to where() like this
User.where(
"first_name like ? or last_name like ? or city like ?",
"%#{search}%", "%#{search}%", "%#{search}%"
)
you can easily provide a hash
User.where(
"first_name like :search or last_name like :search or city like :search",
{search: "%#{search}%"}
)
that makes your query much more readable for long argument lists.
Sounds like you're doing something like this:
Model.where("attribute = ? OR attribute2 = ?", [value, value])
Whereas you need to do this:
#notice the lack of an array as the last argument
Model.where("attribute = ? OR attribute2 = ?", value, value) Have a
look at
http://guides.rubyonrails.org/active_record_querying.html#array-conditions
for more details on how this works.
Was really close. You can turn an array into a list of arguments with *my_list.
Model.where("id = ? OR id = ?", *["1", "2"])
OR
params = ["1", "2"]
Model.where("id = ? OR id = ?", *params)
Should work
If you want to chain together an open-ended list of conditions (attribute names and values), I would suggest using an arel table.
It's a bit hard to give specifics since your question is so vague, so I'll just explain how to do this for a simple case of a Post model and a few attributes, say title, summary, and user_id (i.e. a user has_many posts).
First, get the arel table for the model:
table = Post.arel_table
Then, start building your predicate (which you will eventually use to create an SQL query):
relation = table[:title].eq("Foo")
relation = relation.or(table[:summary].eq("A post about foo"))
relation = relation.and(table[:user_id].eq(5))
Here, table[:title], table[:summary] and table[:user_id] are representations of columns in the posts table. When you call table[:title].eq("Foo"), you are creating a predicate, roughly equivalent to a find condition (get all rows whose title column equals "Foo"). These predicates can be chained together with and and or.
When your aggregate predicate is ready, you can get the result with:
Post.where(relation)
which will generate the SQL:
SELECT "posts".* FROM "posts"
WHERE (("posts"."title" = "Foo" OR "posts"."summary" = "A post about foo")
AND "posts"."user_id" = 5)
This will get you all posts that have either the title "Foo" or the summary "A post about foo", and which belong to a user with id 5.
Notice the way arel predicates can be endlessly chained together to create more and more complex queries. This means that if you have (say) a hash of attribute/value pairs, and some way of knowing whether to use AND or OR on each of them, you can loop through them one by one and build up your condition:
relation = table[:title].eq("Foo")
hash.each do |attr, value|
relation = relation.and(table[attr].eq(value))
# or relation = relation.or(table[attr].eq(value)) for an OR predicate
end
Post.where(relation)
Aside from the ease of chaining conditions, another advantage of arel tables is that they are independent of database, so you don't have to worry whether your MySQL query will work in PostgreSQL, etc.
Here's a Railscast with more on arel: http://railscasts.com/episodes/215-advanced-queries-in-rails-3?view=asciicast
Hope that helps.
You can use a hash rather than a string. Build up a hash with however many conditions and corresponding values you are going to have and put it into the first argument of the where method.
WRONG
This is what I used to do for some reason.
keys = params[:search].split(',').map!(&:downcase)
# keys are now ['brooklyn', 'queens']
query = 'lower(city) LIKE ?'
if keys.size > 1
# I need something like this depending on number of keys
# 'lower(city) LIKE ? OR lower(city) LIKE ? OR lower(city) LIKE ?'
query_array = []
keys.size.times { query_array << query }
#['lower(city) LIKE ?','lower(city) LIKE ?']
query = query_array.join(' OR ')
# which gives me 'lower(city) LIKE ? OR lower(city) LIKE ?'
end
# now I can query my model
# if keys size is one then keys are just 'brooklyn',
# in this case it is 'brooklyn', 'queens'
# #posts = Post.where('lower(city) LIKE ? OR lower(city) LIKE ?','brooklyn', 'queens' )
#posts = Post.where(query, *keys )
now however - yes - it's very simple. as nfriend21 mentioned
Model.where(attribute: [value1,value2])
does the same thing