I am trying to use the composite_primary_keys gem on my application.
I made this "Enterprise" model that have "related" and "branch" attributes. Those 2 are my composite PK.
class Enterprise < ActiveRecord::Base
self.primary_key = :related, :branch
end
Using rails console, I can find my first Entreprise by using e = Enterprise.find([1,1]) without a problem.
The thing is: I can't make it work on my controller...
My show action, for example:
#enterprise = Enterprise.find(params[:id])
It gives me the error:
Couldn't find Enterprise with 'related,branch'=1,1
Parameters: {"id" => "1, 1"}
What am I doing wrong?
params[:id] is a string - you need to create an array out of it:
#enterprise = Enterprise.find(params[:id].split(',').map(&:to_i))
Composite primary key supports for string params for finding an object. The thing is you should not give space between the primary keys. So your param should be like this,
params => {"id" => "1,1"}
#enterprise = Enterprise.find(params[:id])
Try this, it should work.
Related
This query is not working, pease help. I'm trying to include a second and a third deep-level of association.
Pedido > has_one(products_pedido) > has_one(product_size)
#pedidos = Pedido.includes(:pedidos_payments, :products_pedidos => { :product_size } , :estado, :brand, :customer ).where(:is_quote => false)
Ps: I know products_pedido is mispelled according to ActiveRecord good practices :).
Without a stacktrace here's what I suggest:
Assuming your has_one method name is products_pedidos, your issue looks like a problem with your hash syntax.
Your syntax creates a hash with key products_pedidos that returns a hash without a value. This is probably where the error is occurring.
#pedidos = Pedido.includes(:products_pedidos => { :product_size })
What you likely want is this which returns a hash with key products_pedidos with value product_size
#pedidos = Pedido.includes({products_pedidos: :product_size })
The Entire query might look like:
#pedidos = Pedido.includes(
:pedidos_payments,
{products_pedidos :product_size},
:estado,
:brand,
:customer
).where(is_quote: false)
Here's a great post explaining a bit more about ActiveRecord nested relationship loading: Rails - Nested includes on Active Records?. I'd also suggest fixing the naming on products_pedido to follow good naming practices.
I have an ActiveRecord model like this:
class Person < ActiveRecord::Base
attr_accessible :name
end
and need to get a hash mapping Person's ids to their names:
{1 => "Paul", 2 => "Aliyah", 3 => ... }
Now, the obvious way would be
Person.all.collect { |p| [p.id, p.name] }.to_h
However, I don't need to instantiate every Person, I just need the hash. In Rails 4, I can .pluck(:id, :name) instead of collect, however in 3.x, pluck takes only one argument. However I found this workaround to get what I want without loading the models:
Person.all.group(:id).minimum(:name)
Question: will I burn in hell? Also, is there a more elegant way to do this, and are there any drawbacks of this hacky approach that I may not be aware of? Thanks!
Here's a pretty good write up of this situation and various tactics for handling it: Plucking Multiple Columns in Rails 3
My preference of suggested solutions there is to make and include a module:
# multi_pluck.rb
require 'active_support/concern'
module MultiPluck
extend ActiveSupport::Concern
included do
def self.pluck_all(relation, *args)
connection.select_all(relation.select(args))
end
end
end
class Person < ActiveRecord::Base
attr_accessible :name
def self.pluck_id_and_name
result = connection.select_all(select(:id, :name))
if result.any?
# if you are using Ruby 2.1+
result.to_h
# Works in 1.9.3+
Hash[result]
end
end
end
Since the result should be an array of arrays we can use nifty trick to get a hash with the first element as keys and the second as values:
Hash[ [ [1, "Joe"], [2, "Jill"] ] ]
# => { 1 => "Joe", 2 => "Jill"}
See:
Convert array of 2-element arrays into a hash, where duplicate keys append additional values
To avoid loading all of the objects you could do this:
hash = Hash.new
ActiveRecord::Base.connection.execute("SELECT id, name FROM persons").each {|person| hash[person['id'].to_s] = person['name'].to_s}
My company used one of the tactics from Plucking Multiple Columns in Rails 3 before.
But we had trouble upgrading from Rails 3 to Rails 4 because it didn't work in Rails 4.
I suggest using pluck_all gem which has high test coverage in Rails 3, 4, 5, so you will not worry about future upgrades.
I am wondering if it's possible to reference an object's attribute.
The object User have attribute first_name, so normally if we want to update the first name attribute we do:
user0 = User.new()
user0.update_attribute(:first_name, "joe")
now my question is can I update the :first_name attribute through another variable/symbol like so:
user0.update_attribute(:fname_ref, "jack")
user0.first_name #=> has the value jack
I was looking for variable reference like in Perl, but came up nothing in Ruby.
---------- EDIT
I am in the middle of doing the lynda ruby on rails tutorial, and in the middle of creating a module to adjust positions of items in a table.
unfortunately when I first started I named my tables columns differently
pages.page_position, subjects.subject_position, sections.section_position
now the module PositionMover is to be used accross three models, so now
I have a problem since the attributes names are different for each model
so I thought no worry I'll just create a pointer / refference for each model
:position = :pages_position , :position = :subjects_position , :position = :section_position
hence the question , if its even possible to do it.
if its not possible , any suggestion what should I do , so the module can
be used accross three different models , with different attribute names.
sorry I am a newbie.
Symbols are not like variables, they are actually a object type, like String or Fixnum so you can have a variable that is of type symbol.
I think this is what you are looking for:
attribute = :first_name
user0.update_attribute(attribute, "jack")
user0.first_name #=> has the value jack
Update: If you have a String and need to convert to a symbol, (I'm not sure if you need this for update_attribute)
foo = "string"
foo.to_sym #=> :string
Use the alias_attribute . Define into each model like :
Page model
alias_attribute :position , :pages_position
Subject Model
alias_attribute :position , :subjects_position
Section Model
alias_attribute :position , :section_position
And use (Model.position = values) with each model . Hope Its solution of your problem .
You can also use send docs and use symbols or strings to reference the attribute's methods. send can be incredibly useful since it enables you to choose the method that you'll be invoking at runtime.
Eg
user.first_name = "Jack" # set first_name to Jack
# Note: method "first_name=" (a settor) is being used
attribute = "first_name"
user.send attribute + "=", "Jack" # set first_name to Jack
# The string "first_name=" is coerced into
# a symbol
attribute = :first_name
val = user.send attribute # => returns "Jack"
see the definition of update_attribute in the ActiveRecord::Persistence module on github:
def update_attribute(name, value)
name = name.to_s
verify_readonly_attribute(name)
send("#{name}=", value)
save(:validate => false)
end
this leads me to believe you could add the following to your model to achieve that behavior:
alias_method :fname_ref= :first_name=
I'd be interested to know why you want to do that as #Andrew Marshall asked.
I've got a model, Entity.
class Entity
include Mongoid::Document
field :x
field :y
field :z, type => Hash, :default => {} # new field
end
I added a new field to it, a hash. When I try to use it, I get an error. My code is:
e = Entity.first
if e.z["a"] # if there is a key of this in it?
e.z["a"] = e.z["a"] + 1
else
e.z["a"] = 1
end
But, this error with an undefined method get for hash. If I try to create an initializer for it, to set the values in an existing document, it errors with the same error. What am I doing wrong?
Initializer looks like:
e = Entity.first
e.write_attribute(:z, {})
Thanks
Sorted it.
It seems the answer is to set in Mongoid 1.9.5 the hash to:
field :hash_field, :type => Hash, :default => Hash.new
and it can access and initialize it. Not quite understanding why, but happy to have the answer !
Is there any way of overriding a model's id value on create? Something like:
Post.create(:id => 10, :title => 'Test')
would be ideal, but obviously won't work.
id is just attr_protected, which is why you can't use mass-assignment to set it. However, when setting it manually, it just works:
o = SomeObject.new
o.id = 8888
o.save!
o.reload.id # => 8888
I'm not sure what the original motivation was, but I do this when converting ActiveHash models to ActiveRecord. ActiveHash allows you to use the same belongs_to semantics in ActiveRecord, but instead of having a migration and creating a table, and incurring the overhead of the database on every call, you just store your data in yml files. The foreign keys in the database reference the in-memory ids in the yml.
ActiveHash is great for picklists and small tables that change infrequently and only change by developers. So when going from ActiveHash to ActiveRecord, it's easiest to just keep all of the foreign key references the same.
You could also use something like this:
Post.create({:id => 10, :title => 'Test'}, :without_protection => true)
Although as stated in the docs, this will bypass mass-assignment security.
Try
a_post = Post.new do |p|
p.id = 10
p.title = 'Test'
p.save
end
that should give you what you're looking for.
For Rails 4:
Post.create(:title => 'Test').update_column(:id, 10)
Other Rails 4 answers did not work for me. Many of them appeared to change when checking using the Rails Console, but when I checked the values in MySQL database, they remained unchanged. Other answers only worked sometimes.
For MySQL at least, assigning an id below the auto increment id number does not work unless you use update_column. For example,
p = Post.create(:title => 'Test')
p.id
=> 20 # 20 was the id the auto increment gave it
p2 = Post.create(:id => 40, :title => 'Test')
p2.id
=> 40 # 40 > the next auto increment id (21) so allow it
p3 = Post.create(:id => 10, :title => 'Test')
p3.id
=> 10 # Go check your database, it may say 41.
# Assigning an id to a number below the next auto generated id will not update the db
If you change create to use new + save you will still have this problem. Manually changing the id like p.id = 10 also produces this problem.
In general, I would use update_column to change the id even though it costs an extra database query because it will work all the time. This is an error that might not show up in your development environment, but can quietly corrupt your production database all the while saying it is working.
we can override attributes_protected_by_default
class Example < ActiveRecord::Base
def self.attributes_protected_by_default
# default is ["id", "type"]
["type"]
end
end
e = Example.new(:id => 10000)
Actually, it turns out that doing the following works:
p = Post.new(:id => 10, :title => 'Test')
p.save(false)
As Jeff points out, id behaves as if is attr_protected. To prevent that, you need to override the list of default protected attributes. Be careful doing this anywhere that attribute information can come from the outside. The id field is default protected for a reason.
class Post < ActiveRecord::Base
private
def attributes_protected_by_default
[]
end
end
(Tested with ActiveRecord 2.3.5)
Post.create!(:title => "Test") { |t| t.id = 10 }
This doesn't strike me as the sort of thing that you would normally want to do, but it works quite well if you need to populate a table with a fixed set of ids (for example when creating defaults using a rake task) and you want to override auto-incrementing (so that each time you run the task the table is populate with the same ids):
post_types.each_with_index do |post_type|
PostType.create!(:name => post_type) { |t| t.id = i + 1 }
end
Put this create_with_id function at the top of your seeds.rb and then use it to do your object creation where explicit ids are desired.
def create_with_id(clazz, params)
obj = clazz.send(:new, params)
obj.id = params[:id]
obj.save!
obj
end
and use it like this
create_with_id( Foo, {id:1,name:"My Foo",prop:"My other property"})
instead of using
Foo.create({id:1,name:"My Foo",prop:"My other property"})
This case is a similar issue that was necessary overwrite the id with a kind of custom date :
# in app/models/calendar_block_group.rb
class CalendarBlockGroup < ActiveRecord::Base
...
before_validation :parse_id
def parse_id
self.id = self.date.strftime('%d%m%Y')
end
...
end
And then :
CalendarBlockGroup.create!(:date => Date.today)
# => #<CalendarBlockGroup id: 27072014, date: "2014-07-27", created_at: "2014-07-27 20:41:49", updated_at: "2014-07-27 20:41:49">
Callbacks works fine.
Good Luck!.
For Rails 3, the simplest way to do this is to use new with the without_protection refinement, and then save:
Post.new({:id => 10, :title => 'Test'}, :without_protection => true).save
For seed data, it may make sense to bypass validation which you can do like this:
Post.new({:id => 10, :title => 'Test'}, :without_protection => true).save(validate: false)
We've actually added a helper method to ActiveRecord::Base that is declared immediately prior to executing seed files:
class ActiveRecord::Base
def self.seed_create(attributes)
new(attributes, without_protection: true).save(validate: false)
end
end
And now:
Post.seed_create(:id => 10, :title => 'Test')
For Rails 4, you should be using StrongParams instead of protected attributes. If this is the case, you'll simply be able to assign and save without passing any flags to new:
Post.new(id: 10, title: 'Test').save # optionally pass `{validate: false}`
In Rails 4.2.1 with Postgresql 9.5.3, Post.create(:id => 10, :title => 'Test') works as long as there isn't a row with id = 10 already.
you can insert id by sql:
arr = record_line.strip.split(",")
sql = "insert into records(id, created_at, updated_at, count, type_id, cycle, date) values(#{arr[0]},#{arr[1]},#{arr[2]},#{arr[3]},#{arr[4]},#{arr[5]},#{arr[6]})"
ActiveRecord::Base.connection.execute sql