I was wondering if anybody knew of a way to do something like the following:
rails generate model Foo name:string, validates: {:name, uniqueness: true}
That is, whilst declaring a model generator with some attributes, work some rails magic to add your validations at the same time.
There isn't. The rails generate model command is directly tied to database functionality. For example, you should be able to do a command like this rails generate model Foo name:string:uniq. This would force the database to require a unique string for the name. This wouldn't add anything to your foo.rb file.
Here is some more information about rails model generations:
http://travisjeffery.com/b/2012/03/generate-rails-migrations-that-automagically-add-your-change/
As others have said, there isn't currently a way to do this. Most of the special options for the rails generate model command are parsed by the parse_type_and_options method in generated_attribute.rb. The model_generator.rb will then build the model and migration files using this info.
The template for the model file that is created is model.rb. In Rails 4 this template can add in special code for belongs_to, polymorphic, and has_secure_password but not code related to validations.
The template for the migration file that is created is create_table_migration.rb. In Rails 4 this can add in special options for limit, decimal, and precision.
Since Rails 3.2 it has been possible to pass :uniq to the column definition on the rails command line.
The way to do this is relatively simple; just add :uniq after the column and type definitions, e.g.:
rails generate model Foo name:string:uniq
Related
I tried to generate a rails model like so:
rails generate model signal
Which produced this error:
The name 'Signal' is either already used in your application or reserved by Ruby on Rails. Please choose an alternative and run this generator again.
I quickly discovered that "Signal" was a reserved name for models:
Reserved names with ActiveRecord models
Is there any way around this so I can have a model named "Signal", like wrapping the model in a custom Module?
I'm trying to generate some models but they are being generated without attributes.
I'm using a linux system and the rails version is:
rails --version
Rails 4.0.0
I've tried to generate the models using this commands:
rails g scaffold Bsdsd description:string test:string oaso:integer
and
rails g model Asdsd description:string test:string oaso:integer
The first results in this empty class model everything else ok:
class Bsdsd < ActiveRecord::Base
end
The second results in test files, migrations file(that contains the attributes) and this class model:
class Asdsd < ActiveRecord::Base
end
How can I correct this behavior?
Model attributes are inferred from database columns, so you don't need them specified in model classes.
In Rails 3.2 you had (if I remember correctly)
# attr_accessible :description, :test, :oaso
line generated. But protected attributes are deprecated in Rails 4.0 and replaced by strong parameters mechanism.
Nothing you're doing is wrong. But you're checking the wrong files. Look for CreateAsdsdsMigration (in the migrations directory) file and you'll see the auto-generated fields there
For those coming from Grails or Django, note that Rails creates the database FIRST-- not the other way around, where domainclass.groovy or models.py creates the database tables for you AFTER you define them. Look for yourapp/db/schema.rb and inside are all your classes and their field definitions.
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?
I am pretty new to Ruby on Rails, and I was wondering if there was a way to edit the database schema for a model.
For example, I have the Subscriber model in my application -- the way I created it was by using rails generate scaffold Subscriber email:string
But now, I want a name in the subscriber model as well. Is there any easy way to do this? I have put a lot of code in my current controllers and views, so I don't necessarily want to destroy the scaffold, but I would like to edit the model.
Thanks in advance,
hwrd
P.S. I am using Ruby on Rails 3
An ActiveRecord Model inspects the table it represents. You don't actually need to change your model just to add a new field (unless you want to add validations, etc).
What you want to do is make a new migration and then migrate your database up:
rails g migration AddNameToSubscribers name:string
rake db:migrate
Then you can start referencing the name field in your controllers and views.
(This generator command might seem a little magical, but the rails generator recognizes this format and will generate the appropriate add_column and remove_column code. See the Rails migration guide for further reading.)
If you mean changing the database schema of your model, you'll want to use migrations.
You'll do things like
add_column :city, :string
remove_column :boo
http://guides.rubyonrails.org/migrations.html
If you do only mean finding models and updating the data inside each instance, go with #apneadiving's answer.
I have a database with tables. I want to create a model in my Rails app from existing table. As i know, such functionality is available, and is done as follows:
script/generate scaffold model_name --skip-migration
Of course, i defined my database in database.yml file. Scaffold generated for me a model with controller and views. My table name is not as it must be for Rails(it is incorrect, not following conventions), i added set_table_name to my controller. But, when i am calling the index method, on my page i have only set of # symbols, but not a data from database. In my index.html.erb i have only generated code by scaffold. How can i print out my database data?
Have you generated a schema file from your existing database? If you run the command
rake db:schema:dump
and then re-generate your scaffold this should fix the problem.
Additionally you may wish to check out Dr Nic's Magic Model generator. This will generate models for all of your existing tables and attempt to guess the relationships. This will probably not work if your table naming is not understandable by rails.
UPDATE
I do not generally use the default scaffold however I have tested this myself and it appears that if you skip the migration and do not pass any column name/type pairs then the scaffold generator will not create anything in the template to render the columns.
You have two choices here either
Pass in the column name pairs as well as skip-migration or
Download Ryan Bates Nifty Scaffold generator which will create the scaffold with the column names even if you specify --skip-migration