I have two classes: Article(has_many comments) and Comment(belongs_to article). My database is empty, postgresql.
I need download information in db from seeds.yml using seed.rb. Code in seeds.rb must contain class HashWithIndifferentAccess.
I'm newbie in RoR and I cannot find some good information about it.
Related
Hello every one I'm new to ruby on rails. I go through the following code in which I'm told that database schema is being loaded through this code:
Account.current = Question.find(2)
Question.last
I'm unable to understand about how schema is being loaded. what this code is actually doing. Please help
Start with Rails Guides (Active Record). Here is the documentation.
Also, look at AREL. Here is the link to it on GitHub.
This article explains how arel converts ruby queries into sql statements.
I am trying to access all records of a table that has an underscore in its name.
For example if I have table in my schema that is called trips I can do Trip.all in rails console. But what do I do if my table name contains an underscore (e.g. users_foods)
I tried the following options:
Users_food.all
User_food.all
User_foods.all
etc.
All of the above did not work, any suggestions?
Figured it out
One can access the data with UserFood
For a table named users_foods, ActiveModel should provide you with a corresponding Rails model UsersFood, to fit Ruby/Rails object naming convention. Try that.
Class names Users_food or User_food, etc. do not conform to Ruby convention.
I had the same problem when creating bonus_histories table. And didn't work any of the answers until I found out why.
I have made only rails g migration BonusHistory
and it was the problem. My rails console didn't find BonusHistory at all because I had no model.
So I had to first rollback the migration rake db:rollback STEP=1, then deleted the migration file and finally made
rails g model BonusHistory
and after migrating that table, when I enter rails console, I can successfully ask for BonusHistory.count
I have used two different databases for my Rails application: MongoDB and MsSQL using Mongoid and activerecord-sqlserver-adapter adapter respectively. Everything is well but there is a problem while generate Model.
The problem is "how can I generate the model that relates to MongoDB or MsSQL differently?"
For example: I want to generate People model relates to MongoID and Animal model with MsSQL. While I generate with command: rails g model Animal name:string it generates the model related to mongoid. How can I generate the model Animal with ActiveRecord that means related to MsSQL.
Please help me.
Thanks
Based on Using Active Record generators after Mongoid installation? I believe this should work:
rails g active_record:model Animal name:string
First let me just check that I've understood your question correctly:
You have 2 databases and a series of models/migrations, and you want a way to tell rails which database to use when running a migration and accessing the database using your model?
If I'm in the right area then you need to add a method to your migration which overrides the default connection() method in ActiveRecord::Migration.
def connection
ActiveRecord::Base.establish_connection(:conn_name).connection
end
Where :conn_name is the name you gave your connection settings in config/database.yml
within your models add the line
establish_connection :conn_name
to the top of your model file and the model will now know which DB to connect to.
So the quick and dirty way that I have handled this in the past (due to my dev team keeping mongoid in the gem file for legacy reasons) is to comment out the out mongoid when you have to do migrations run a bundle, generate and run you migration then uncomment and run bundle again. This is far from best practices but it should work.
I have a Ruby on rails 3.2 application. I want to enable text based search on a model that has a lot of data already populated in it. Suppose the name of the model class is Post. I am planning on using elasticsearch since I heard it is one of the best real-time search engines around and I am using tire gem so that my application can interact with elasticsearch.
As I am new to elasticsearch I am having trouble creating indices for the existing data for the model. I am using mongodb as the backend database. Can anyone tell me how to import the indices.
I have already tried
Tire.index "posts" do
import Post.all
end
The error that I got was :
BSON::InvalidObjectId: illegal ObjectId format: Career Guidance
from /Users/anirvan/.rvm/gems/ruby-1.9.3-p125/gems/bson-1.5.1/lib/bson/types/object_id.rb:126:in `from_string'
Can anyone help me out here ?
I use Mysql and this code in bash(from railscasts.com):
rake environment tire:import CLASS=Post FORCE=true
http://www.elasticsearch.org/guide/appendix/clients.html
tire: Ruby API & DSL, with full Rails ActiveModel compatibility and mongoid integration through mebla.
Try it, maybe help you.
rails generate migration
rails generate model
rails generate scaffold
rails generate controller etc.
How these differ?
According to rails guides:
Using generators will save you a large amount of time by writing boilerplate code, code that is necessary for the app to work, but not necessary for you to spend time writing. That’s what we have computers for.
rails generate commands family used to provide simple and easy way for developer to create different object types.
rails generate migration - creates DB migration script in db/migrations directory so developer can setup his DB.
rails generate model - creates model class with associated migration, test and fixtures (test data).
rails generate scaffold - creates all nedded classes with basic logic and presentaion. It creates controller (with simple CRUD logic), model, fixtures, functional and unit tests.
rails generate controller - creates controller with associated functional tests, helper and basic views templates.
You can read more here: http://guides.rubyonrails.org/command_line.html#rails-generate
They differ in the sense that they generate different stuff.
migration will generate a database migration file,
model will generate a model(with a migration and a spec by default)
scaffold will generate a scaffold of a resource
and controller will generate a controller.
generate means it will create the files for you with boiler plate code already in place(you will still need to edit them though..but scaffold can get you working with a basic application already)
Read more about it here: http://guides.rubyonrails.org/command_line.html#rails-generate
rails generate is a command line script for quickly generating the code for various Rails' constructs.
In the example you give they differ by what they produce, with the first argument being the type of code generated. For example if I wanted to create a User model I would run:
`rails generate model user`
The model file, test file and migration would be created for me.
You should read the Rails' documentation to find more.
**rails generate model user:
The above command create a Template Object that is a mirror image of the database table.
For example, if you have a database table that is named users that has a name:string, and email:string field,then "rails generate model user" create an Object that mirrors that user table with a few addition.
Here are the similarity they both have name:string,email:string the both have the word user.
The difference are few but significant: user is Capitalized in the model name like "User".
The Table add create_by and updated_by automatically.
migration:db create the database mirror using the model as a model.RECURSION ANYONE?