I'm new to rails...I made a scaffold "Reviews" but want to add another field "ratings", as an integer. I did the following:
added t.integer :ratings in the migration file..ran rake db:migrate
in spec folder: added it in views/app/ edit, index, new, show
in app/views/app added it in the json files
in app/controllers/app added it in the review_params function
still however whenever I try to reference (by showing a Review) it I get
undefined method `ratings' for #
There must be something else I need to add somewhere to have it be part of my Reviews scaffold. I've been trying to figure it out for 5 hours but still have not. When I try to remake a scaffold and run rake db:migrate I get an error saying that the databases already exist so I would like to just manually add it to my existing one if possible, I just can't seem to figure out how even though I've already done it once for a string.
Any help is appreciated thank you.
To add an integer field to a model you can do something like this.
rails generate migration AddRatingToReviews rating:integer
This should handle everything for you by generating a new migration file like so.
class AddRatingsToReviews < ActiveRecord::Migration
def change
add_column :reviews, :rating
end
end
Then you can run rake db:migrate to add the column to your review model.
NOTE: Before doing all of this, please delete all your manual changes. If necessary use rake db:rollback which will rollback your most recent rake db:migrate.
Recommendation
If you are new to rails and don't understand MVC, I suggest not using scaffolding because you'll have a tough time knowing what it is doing. Go through this awesome tutorial by Michael Hartl to really learn rails quickly. http://ruby.railstutorial.org/
*Awesome gem *
Use the annotate gem to display the attributes contained within your model directly in your name_of_model.rb files.
https://github.com/ctran/annotate_models
rails generate migration AddRatingsToReviews ratings:integer
Then
rake db:migrate
If you have not done any major changes in your generated scaffold.
Simplest way to get the ratings across views would be as below:
Rollback the changes that you have migrated
rake db:rollback VERSION=version_number
Where replace version_number with the version_number prefixed on your migration file.
For eg: If your migration filename is 20140314190622_create_reviews.rb then command should be
rake db:rollback VERSION=20140314190622
Destroy the scaffold of Review
rails d scaffold Review
After this generate the scaffold again with the integer field
rails g scaffold Review ratings:integer .... ## Add other field in place of ....
Related
I currently have a migration and I simply want to add a couple more values to this migration such as to_limit and from_limit along with their default values (5&10). How should i do this?
class AddUserToCompany < ActiveRecord::Migration
def change
add_column :companies, :user, :jsonb, default: {"to_dist"=>50, "from_dist"=>70, "trs_one"=>100, "trs_two"=>120}
end
end
I added some changes which also requires "to_limit"=>5 and "from_limit"=>10. Please suggest on how to add a new migrate file and add the changes.
Rails version - 4.2.11
This is my first time working with a rails application. So i am really confused on how to proceed with this.
1.If this changes are in progress (not already used by other) then you can rollback this migration by command
rollback last migration
rake db:rollback STEP=1
In order to rollback ONLY ONE specific migration
rake db:migrate:down VERSION=20220905201547
and after applying changes, run rake db:migrate
If migration was created earlier then you can create new migration to apply your changes
generate new migration by command
rails generate migration nameOfMigration
I hope this helps
So I've been going through a lot of rails tutorial, and I get that the default for adding a new column to a database is , for example,
rails generate migration add_reset_to_users reset_digest:string reset_sent_at:datetime
The above will add a reset_digest in the form of a string and reset_sent_at in the form of a date to the migration add_reset_to_users
My questions is what if I am clumsy one night at 4 AM and only call the following
rails generate migration add_reset_to_users reset_digest:string
I completely forgot about reset_sent_at but want to implement it the next morning. I made the mistake of adding the link directly to the db file, which was a huge mistake.
In this case what should I do? Do I simply call a new migration such as
rails generate migration add_reset_sent_to_users reset_sent_at:datetime
or is there an even better way?
first, if you have not run your migration, you can directly open the migration file, and add your column to the file, as
def change
add columns :table_name :column_name :column_type
end
In your case, you will modify the file as,
def change
add columns :users :reset_digest :string
add columns :users :reset_sent_at :datetime
end
and then run
rake db:migrate
if you have already ran your migration, and you have not run any other migration after that, you can undo it, by
rake db:rollback STEP=1
and then edit the migration file, and run your migration
Rule of thumb for migrations in Rails is that you always create a new migration file unless you have not already shared your code with others, i.e. pushed to remote repository, otherwise you can just change the old migration after running $ rake db:rollback and everything will be fine, and nobody will know about it, and won't affect other developers work(since it's still on your local repository).
So, I'd encourage you to create a new migration if you have already committed and pushed the code onto remote repository, and changing the old migration file again will hurt other developers productivity. In case of any confusion, always create a new migration:
rails generate migration add_reset_sent_to_users reset_sent_at:datetime
I think it depends what state your rails app is in.
If you were working on a production app then editing migrations is not advisable due to data loss and changes should be made with a new migration.
If your working locally in development then I would edit the migration directly and add the missing column and rerun your migration.
Don't be worried about editing you migrations, just remember to rake db:rollback the migration you are editing before making changes or you will encounter errors.
This is where changing your migration from:
def change
add_column('users', 'reset_digest', :string)
add_column('users', 'reset_sent_at', :datetime) # Would have to perform rollback before adding this line
end
to:
def up
add_column('users', 'reset_digest', :string)
add_column('users', 'reset_sent_at', :datetime) # Added after migration
**rake db:migrate
end
def down
remove_column('users', 'reset_digest', :string)
remove_column('users', 'reset_sent_at', :datetime) # Add this after rollback
**rake db:rollback
end
Allows you to make changes to your migrations before you rake db:rollback
This requires a bit more code but I find it easier when I'm building a new app and things are changing frequently.
I'm getting this error message when I run the above code generator: (I'm just a beginner)
invoke active_record
Another migration is already named create_posts.....
Use --force to remove the old migration file
What do I type into the terminal window to "use force"
You are getting the following error because you already have a migration named create_posts in your rails application.
invoke active_record Another migration is already named create_posts..... Use --force to remove the old migration file
So, what you need here is first remove the existing migration and then generate the scaffold.
rails d migration create_posts
rails generate scaffold post title:string body:text
Or
You could generate the scaffold using --force option
rails generate scaffold post title:string body:text --force
EDIT
As per your comment:
I did that and then a whole bunch of code appears with the lines of
code sating invoke...exist...identical.
It means that you already ran a scaffold once for Post successfully and you are trying to generate the scaffold again.
I am not sure why you are doing that BUT identical is not an error. Its just that Rails is telling you that you already have a particular file so I am not creating again.
You can reset your database if you don't care about losing your database with this :
b rake db:reset
This will re-reun all your migrations. But take note! Your migrations should be able to run from one end to the other. So if something is "not working" with the regular rake db:migrate, then you should resolve that issue is specifically.
Show me a more descriptive error, and I can tell you more.
You should add other migration in order to change your Post table as you want it to be.
Your could begin with rails g migration and see the help provided.
If you want to get away with it you can delete the migration that created the Post table (but I guess you would need to delete the DB)
After the first time you generate a scaffold, by default Rails will not overwrite the existing scaffold. This is to ensure that you don't accidentally destroy a lot of work.
If you're really sure you want to regenerate the scaffold and delete any changes you might have made to any of the generated files, try:
rails generate scaffold post title:string body:text --force
I created a new scaffold (I assume that's how that process is described) as such:
rails g scaffold status name:string context:text
However I intended to type "content" instead of "context". I've executed the migration but now have no idea how to make the change across the app.
I am extremely new to Ruby, so I am sure the answer is trivial, I just have had a hard time searching when I hardly know the verbiage within the framework to search for.
Run
bundle exec rake db:rollback
edit your migration and run
bundle exec rake db:migrate
next, edit your newly generated _form.html.erb, show.html.erb and index.html.erb views and your status_params method in controller and it should be enough.
I am a Rails beginner and trying to understand how rails migration works.
I have created a scaffold like:
script/generate scaffold Item col1:string col2:text
rake db:migrate
I would like to add another col4 using migration:
I created a migration as follows:
class AddCol4 < ActiveRecord::Migration
def self.up
add_column :items, :col4, :numeric
Item.reset_column_information
end
def self.down
remove_column :items, :col4
end
end
When I run rake db:migrate the new column gets added. However the view is out of sync.
Am I supposed to manually add the new column to the view? Is there a way to auto-regenerate the model/view using the new table columns?
Sorry, it is a basic question but from my experience with other frameworks, it should have been automatic.
The rails guide on migration does not make this obvious regarding how the synchronization is supposed to work after you perform a migration.
Unfortunately you will need to modify the view manually. The view is created by running the script/generate scaffold command. Migrations only change the database. Technically, you can rerun the scaffold command and have it regenerate the view. It will ask you if you want to overwrite the previous file, however, if you go this route, you will still need to specify ALL of the columns that you want. You can't simply add some here and there.
If you are early in development, then you might take this route. Simply run
script/destroy scaffold Item
and then rerun
script generate scaffold Item col1:string col2 string col3:numeric
There are some dynamic scaffolding extensions available such as ActiveScaffold if you are creating something that only a few users will see, but I would recommend doing the HTML yourself as it will always come out the way you want.
I can't seem to find any of the other dynamic scaffolding plugins. There used to be quite a few...