I already have a database with the right structure.
I would like to create a rails app just to read into this database, I don't want to insert neither update etc...
Actually, I would like to use rails but handle myself the creation of the database and tables.
Is it possible ?
I've commented every lines into "create" def into the migration file, it works but is there another way ?
Thank you.
rails g model ModelName --skip-migration
You might be able to use this Gem.
gem 'rmre', '~> 0.0.8'
It allows you to create models from an existing schema.
See documentation here: https://github.com/bosko/rmre
Related
How can activerecord objects be edited externally with scripts? I'm currently using the activerecord-import gem to insert objects into the database. Is it possible to edit existing records using this gem or using another tool or gem?
That's a bit unspecific. There are quite a few methods. Here's the best:
You can run rails on the console. Try irb in your project's directory, and you're on a REPL that allows you to run code live. Just try something like:
that_guy = User.find(4)
that_guy.name = "John"
that_guy.save!
(Replace User, 4 and name with a model you have, a record's id and some string attribute).
And of course you can also just run a file of ruby against your project: rails runner your_script.rb
And, if I misunderstood you: you can of course access the database through any other means/languages/libraries.
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 model called MyArticle. When I try to use the command
rails generate migration AddtestToMyArticle test:string
the migration file contains only empty up/down methods. Having done this previously on a single word model name, it worked just fine and the migration up/down methods had the appropriate code.
I tried "AddtestToMy_Article" but that didn't work either. What do I need to do to work with my compound model name and the generate migration command?
You need to use
rails generate migration AddColumnToMyArticle test:string
When using 'AddColumn' you will have the appropriate code in your migration.
I just looked back over this, and while my answer is correct, it's better to have a more descriptive migration name. The user below who noticed the capitalization is right in that if you don't have each new word capitalized, Rails won't pick up on what exactly you're trying to do. So, in your question you have AddtestTo... but it should be AddTestTo....
It seems to work if you use underscores rather than CamelCase
rails g migration add_test_to_my_article test:string
Hope this helps
rails generate migration AddNewFieldToMyArticle new_field:string
I have a bunch of rails models that I'm re-writing into a single model to simplify my code and reduce unnecessary tables.
I'm wondering what the best way to delete a model class and its table is. I want past migrations to still succeed, but I don't want to leave the empty models lying around.
Do I have to manually delete the old migrations that reference these models, then manually delete the class files?
Does anyone have any tips for the best way to do this?
All in one solution.
Run the following commands:
rails destroy model ModelName
rails g migration DropTableModelName
The former will generate a new migration file which should looks like this:
class DropTableModelName < ActiveRecord::Migration
def change
drop_table :model_name
end
end
Now run db:migrate and you're done.
If you'd like to completely get rid of of a model and its table do this:
rails destroy model Name
The question is a bit stale now, but I just did:
rails destroy scaffold <ModelName> -p
The -p flag shows "pretend" output, which is good for seeing what will happen. Remove the '-p' flag and the results will match the output. This cleaned the entire collection of M-V-C files + testing + js files + the original migration, no problem.
I guess if you are one who likes to hand edit your migrations and include multiple steps in each, losing the original migration could break db:setup, so buyer beware. Keeping one action == one migration file should avoid this potential snafu.
What about doing ruby script/destroy model? That should take care of the model and the migration.
Depending on how far into development or production you are, you may want to migrate the models out safely using a migration to remove/backup data or what not. Then as bobbywilson0 suggested, using
script/destroy model
or if you rspec anything
script/destroy rspec_model
This will remove any spec tests as well.
Or you can always just drag them to the trash folder.
You can take a look at this one at rails guide.
But I suggest, if it is possible, you should delete the models and all references to the models. This will probably save time later as you don't need to maintain the dead code in the codebase.
If you'd rather have a manual based answer:
First run the following command to identify which migrations you want removed:
rake db:migrate:status
Feel free to grep -i on it too if you're confident of your naming scheme.
Make note of all the "add x to model name" and similar alterations to your Model. These can be removed using:
rails d migration AddXToModelName
Do this for every migration besides the initial create migration. The following command will take care of the initial create migration and the files associated with the model:
rails d model ModelName