I've been looking at this repository
https://github.com/stungeye/ActiveRecord-without-Rails to understand how can I implement activerecord without rails.I got some problems. At first I got this error when I tried to run this class:
require 'active_record'
ActiveRecord::Base.establish_connection(adapter: 'mysql2', database: 'rbuserroom')
# Can override table name and primary key
class User < ActiveRecord::Base
self.primary_key = 'user_id'
def initialize(id, email)
#user_id = id
#user_email = email
#user_room
end
def create()
self.save
end
# accessor get and set method
attr_accessor :user_room
attr_reader :user_id, :user_email
end
usr = User.new(1, "user#user")
usr.create()
but I got this error:
Traceback (most recent call last):
1: from -:25:in `<main>'
/home/felipe/.rbenv/versions/2.7.5/lib/ruby/gems/2.7.0/gems/activerecord-6.1.4.1/lib/active_record/inheritance.rb:52:in `new': wrong number of arguments (given 2, expected 0..1) (ArgumentError)
it seems that active record doesn't accept the parameters in the creation of the class, in fact after that i noticed that the classes in this example don't contain anything inside, how would active record define the columns of the tables?
i'm used to java jpa and springboot that i have to define all the attributes of the class.
besides i don't know if the active record is really working.
I just want that when I create a new user with my user class, the information persists in the database as an insert, or that it updates when I make a change to my object attribute value.
With ActiveRecord you don't need to specify the column names. It detects them from the DB.
You can just write:
require 'active_record'
ActiveRecord::Base.establish_connection(adapter: 'mysql2', database: 'rbuserroom')
class User < ActiveRecord::Base
self.primary_key = 'user_id'
end
usr = User.create(user_id: 1, user_email: "user#user")
You can read more about creating models in the docs. Especially in 3 Creating Active Record Models
Related
Has anyone experienced this issue on mapping table in ActiveRecord when table name need a schema name as a prefix (oracle)?
Gemfile
gem 'activerecord', '4.2.4'
gem 'activerecord-oracle_enhanced-adapter', '1.6.7'
....
db_helper.rb
class Student < ActiveRecord::Base
self.abstract_class = true
self.table_name_prefix = 'OPT_ABC.'
self.table_name = 'STUDENT'
def self.list_student
puts Student.take(1) #testing
end
end
The actual table name looks like:
SELECT * FROM OPT_ABC.STUDENT;
I am able to connect to the database instance, but when the code gets line:
puts Student.take(1) # SELECT * FROM STUDENT LIMIT 1
I get the following error:
ActiveRecord::StatementInvalid:
table or view does not exist: SELECT "STUDENT".* FROM "STUDENT"
I am looking for solution on how to handle 'OPT_ABC." table prefix. Please share your solution.
It looks like the problem is that you're trying to use both self.table_name_prefix= and self.table_name= together when you should be using one OR the other.
First let's consider how both self.table_name_prefix= and self.table_name= work.
self.table_name_prefix=
According to the documentation, self.table_name_prefix= works by prepending the passed in value to the table name that ActiveRecord automatically generates based off of the name of the class.
So, if the class name is Student and you do self.table_name_prefix = 'OPT_ABC.', your table name will be OPT_ABC.STUDENTS. Note that the generated table name is plural (and ends in an s).
self.table_name=
According to the documentation, self.table_name= sets the table name explicitly. This means that it completely overrides the table name to the value that you pass in.
So, if you do self.table_name = 'OPT_ABC.STUDENT' your table name will be OPT_ABC.STUDENT.
So, given that, to set the table name to OPT_ABC.STUDENT, you should be able to simply pass the value into self.table_name like this:
class Student < ActiveRecord::Base
self.abstract_class = true
self.table_name = 'OPT_ABC.STUDENT'
def self.list_student
puts Student.take(1) #testing
end
end
I have a subclassed ActiveRecord model which uses a separate table to store records and friendly_id (4.1.0.beta.1) to generate slugs. Problem is friendly_id is using the parent class's table to check for existing slugs, instead of using the child table. Basically I'd like friendly_id to scope its checks to the right table.
Example:
class Parent
friendly_id :name, :use => :slugged
end
class Child < Parent
self.table_name = 'children'
end
Parent.create(name: 'hello').slug
> 'hello'
Child.create(name: 'hello').slug
> 'hello--2'
I want friendly_id to generate the 'hello' slug for the second create, because there are no records in the children table with that slug. Is there a way to configure or monkey patch the class friendly id uses for its queries?
EDIT: added friendly_id version for future reference
I'm posting my own solution to this problem, just in case someone is having the same problem. I should reiterate that this problem was found on version 4.1.0.beta.1 of the friendly_id gem (which at the time was the most recent version), so this issue may not occur any more.
To solve this problem, I basically configured slug_generator_class to use my own class, so I could monkey patch the culprit method.
In my model:
friendly_id do |config|
config.slug_generator_class = SubclassScopableSlugGenerator
end
In an initializer, I overrode the FriendlyId::SlugGenerator.conflicts method so I could access the sluggable_class var:
# Lets a non-STI subclass of a FriendlyId parent (i.e. a subclass with its
# own dedicated table) have independent slug uniqueness.
class SubclassScopableSlugGenerator < FriendlyId::SlugGenerator
private
def conflicts
# this is the only line we're actually changing
sluggable_class = friendly_id_config.model_class
pkey = sluggable_class.primary_key
value = sluggable.send pkey
base = "#{column} = ? OR #{column} LIKE ?"
# Awful hack for SQLite3, which does not pick up '\' as the escape character without this.
base << "ESCAPE '\\'" if sluggable.connection.adapter_name =~ /sqlite/i
scope = sluggable_class.unscoped.where(base, normalized, wildcard)
scope = scope.where("#{pkey} <> ?", value) unless sluggable.new_record?
length_command = "LENGTH"
length_command = "LEN" if sluggable.connection.adapter_name =~ /sqlserver/i
scope = scope.order("#{length_command}(#{column}) DESC, #{column} DESC")
end
end
In a sample Rails 3.2.8 app (on Ruby 1.9.3) there is the following simple setup:
class Account < ActiveRecord::Base
has_many :line_items
def subtotal
line_items.sum(&:price)
end
end
class Line_Item < ActiveRecord::Base
belongs_to :product
def price
product.price * time
end
end
account = Account.new
account.line_items.build do |item|
item.years = 4
item.product = Product.last
end
account.subtotal
#=> TypeError: nil can't be coerced into BigDecimal
As above the subtotal method fails with a conversion error. In subtotal I checked the type returned by line_items.class and got Array. If I update the definition of subtotal to either of the following, the method works:
line_items.to_a.sum(&:price)
#=> #<BigDecimal:7ff4d34ca7c8,'0.0',9(36)>
line_items.map(&:price).sum
#=> #<BigDecimal:7ff4d3373b40,'0.0',9(36)>
Why does the initial definition of line_items.sum(&:price) fail?
This appears to be a bug in Rails (at least in 3.2.8).
In Rails 3.2.8, the has_many association is dynamically defining collection.sum.
Though this isn't reflected in A Guide to Active Record Associations
or ActiveRecord::Associations::ClassMethods API docs; it is briefly listed in the API under the "Collection associations (one-to-many / many-to-many)"
chart, but not referenced again.
According to the code, it will always try to hit the database using a SQL sum.
However, in this particular instance, the model isn't saved. So there's nothing
in the database.
So to clear that up a little:
account.line_items.sum(&:price) # Uses Collection#sum, goes to database
account.line_items.map.sum(&:price) # Uses Enumerable#map then Enumerable#sum
This has been logged under issue #7928; which appears related to issue #5215: "finders and scopes on has_many association on new object incorrectly query db for null foreign keys".
I wrote an app where I plan to save user data via DataMapper and sqlite3, and inventory items (several of them) using GDBM. When I run this with irb, User.new and inventory methods works fine however DataMapper says that my user model is not valid and does not save it. I worked with DataMapper previously and never encountered such an error, in fact I used the same user model (with password salt and hash) without any errors in a sinatra-datamapper app.
To be clear, I intend to save both the username and 'the path to the gdbm database file' as a string in datamapper. The gdbm creates its own db file and all methods work fine without complaints and all data is persistent. Since I am not trying to save the gdbm object but only a string in datamapper, I think there should be no problem of validation.
DataMapper::Model.raise_on_save_failure = true does not give a specific description of the error but save! method gives the following error:
DataObjects::IntegrityError: users.name may not be NULL (code: 19, sql state: , query: INSERT INTO "users" DEFAULT VALUES, uri: sqlite3:/home/barerd/game_inventory/users.db?scheme=sqlite3&user=...... but name attribute is not empty as I checked in irb.
Maybe the error originates from sqlite but I have no knowledge to test that. Can someone guide me how to inspect this error?
require 'gdbm'
require 'data_mapper'
require 'dm-validations'
DataMapper.setup :default, 'sqlite://' + Dir.pwd + '/users.db'
class User
attr_reader :name, :inventory_db
include DataMapper::Resource
property id, Serial
property :name, String, :required => true, :unique => true, :messages => { :presence =>...... etc }
property :inventory_db, String
def initialize name
#name = name
#inventory_db = Dir.pwd + '/#{name}_inventory.db'
end
def inventory
GDBM.new #inventory_db, 0644, GDBM::WRCREAT
end
..several methods related to inventory..
end
DataMapper.finalize.auto_migrate!
Googling further, I found out that
there is a guard around defining property getter in dkubb/dm-core
via this link. After removing getter methods from the model, everything worked fine.
I have a simple user model
class User < ActiveRecord::Base
has_one :user_profile
end
And a simple user_profile model
class UserProfile < ActiveRecord::Base
belongs_to :user
end
The issue is when I call the following build method, without calling the save method, I end up with a new record in the database (if it passes validation)
class UserProfilesController < ApplicationController
def create
#current_user = login_from_session
#user_profile = current_user.build_user_profile(params[:user_profile])
##user_profile.save (even with this line commented out, it still save a new db record)
redirect_to new_user_profile_path
end
Anyyyyyy one have anyyy idea what's going on.
The definition of this method says the following but it's still saving for me
build_association(attributes = {})
Returns a new object of the associated type that has been instantiated with attributes and linked to this object through a foreign key, but has not yet been saved.
http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#method-i-has_one
Ok, I'm sure experienced vets already know this, but as a rookie I had to figure it out the long way...let me see if I can explain this without screwing it up
Although I was not directly saving the user_profile object, I noticed in my logs that something was updating the user model's last_activity_time (and the user_profile model) each time I submitted the form (the user model's last_activity date was also updated when the logged in user did various other things too - I later realized this was set in the Sorcery gem configuration).
Per http://api.rubyonrails.org/classes/ActiveRecord/AutosaveAssociation.html
AutosaveAssociation is a module that takes care of automatically saving associated records when their parent is saved. In my case, the user mode is the parent and the scenario they provide below mirrors my experience.
class Post
has_one :author, :autosave => true
end
post = Post.find(1)
post.title # => "The current global position of migrating ducks"
post.author.name # => "alloy"
post.title = "On the migration of ducks"
post.author.name = "Eloy Duran"
post.save
post.reload
post.title # => "On the migration of ducks"
post.author.name # => "Eloy Duran"
The following resolutions resolved my problem
1. Stopping Sorcery (config setting) from updating the users last_activity_time (for every action)
or
2. Passing an ':autosave => false' option when I set the association in the user model as follows
class User < ActiveRecord::Base
has_one :user_profile, :autosave => false
end