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.
Related
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'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 ....
I was attempting to add a tagging model to my rails blog. But I accidentally generated a "Tags.rb" model as opposed to "Tag.rb", after reading the guide I realized that making "tag" plural was a mistake when it comes to model. I rolled back the migration using
rake db:rollback
and then
rails destroy model Tags.rb
and this was what i got back
invoke active_record
remove /home/migration/templates/create_table_migration.rb
remove app/models/tags.rb.rb
invoke test_unit
remove test/models/tags.rb_test.rb
remove test/fixtures/tags.rbs.yml
When I come back to the model folder though its still there.
Please help :)
Just give
rails destroy model Tag
Try using tags plural without the additional .rb, like
rails destroy model Tags
Hope this helps
You can manually delete the files, or just manually remove the "s"s.
try this
bundle exec rake db:rollback
and then delete your model as
rails destroy model <model_name>
now totaly deleted.
You can delete the migration files in migrate folder and model in your model folder and then you can again create new one which you wants.
you have to run that commands
rails g model tag
Then migrate database
rake db:migrate
First off, when generating a Rails model using rails generate model, don't add .rb to the end of the model name. Rails automatically does that so if you add .rb yourself then you end up with a model named Tag.rb.rb, which is invalid.
You're running the remove generator with "Tags.rb". Did you generate the model originally using rails generate model Tags.rb? If you did, then running rails destroy model Tags.rb will hopefully remove all the files, but since the model name is invalid, it might not work as expected (your use case is outside the intended use case of the generator). If you originally generated the model using rails generate model Tags, then running rails destroy model Tags should work.
If you originally invoked rails generate model Tags.rb, and running the remove command isn't working (which again, in understandable given that Tags.rb is an invalid name--would have been nice if the generator had originally prohibited you from generating a Tags.rb.rb file, but you can't have everything):
If you can afford to destroy your database and rerun all the migrations, the easy solution will be to manually remove the added files, destroy the database, and rerun all migrations. Then you can add the correct model using rails generate model Tag.
If you can't afford to destroy your database, then you'll need to manually find the problem migration in the migration's folder, run the down command on that migration, and then manually delete that migration file and all the other files.
When I ran bundle exec rake db:test:prepare I got the following:
rake aborted!
Multiple migrations have the name CreateMicroposts
To check the status of my migration files, I ran
rake db:migrate:status
And got:
Status Migration ID Migration Name
------- --------------- -----------------
up 20120616205407 Create users
up 20120622103932 Add index to users email
up 20120622114559 Add password digest to users
up 20120628095820 Add remember token to users
up 20120704123654 Add admin to users
down 20120706103254 Create microposts
up 20120707073410 Create microposts
As you can see, I have two migration files with the exact same names and the exact same code in them. It's only their statuses differ, i.e. Up and Down.
What does Up and Down signify?
And which one can I delete, if I have to?
The problem is that you have two different migration files containing the header
class CreateMicroposts< ActiveRecord::Migration
rake db:migrate:status does not check the status of your migration files. It tells you what migrations will be applied if you run rake db:migrate. The up/down labels are pretty much self-explanatory: it tells you whether the migration will be applied via the up method or the down method. The up method is ran when you migrate and the down when you rollback a migration. You can make some further reading about Rails migrations here.
up is the method called when "evolving" (ie migrating to a new schema), while down is the method called when "regressing" (ie migrating to an older schema version, because one of your changes doesn't suit you). db:migrate calls up, db:rollback calls down. In recent versions of rails, there's change that handles both at the same time.
As for the deletion... I don't do activerecord much these days, but I think you're free to do whatever you want with your files. I don't think deleting a duplicate file will do any harm, and if it does.. Well, you use source control, right ? :)
I am new to Ruby on Rails . This might be a very foolish question.
I have created a migration using
rails generate migration Kapol name:string position:integer
rake db:migrate
Then using phpmyadmin i copied the database already present
I then opened up rails console
My question is can i use the method Kapol.find(1)??
because when i tried it using singular or plural it says
unitialized constant:Kapol
I know that there has to be a method but where to specify it?
You must generate a model in case to create a table for it, because the migration is usually used to modify existing tables.
It might be confusing that the model generator also creates migration file in your migrations folder. The only difference is that the model generator also generates initial code to create table, on the other hand, the migration generator creates only migration file without initial code.
rails generate model Kapol name:string position:integer
More information: http://guides.rubyonrails.org/getting_started.html#generating-a-model
If you're very new to Ruby on Rails, probably the best thing for you to do is create a scaffold, which gives you your migration file, your model file, your controller file, and various view files, test files, etc. etc., which all work well together. Then you can play with these and build up from there.
rails generate scaffold Kapol name:string position:integer
If you're happy with the migration that was automatically generated, then rake db:migrate and you're all set.
As Andrew says below, you can also just generate any of those files one at a time by replacing 'scaffold' with 'model', etc.
Your Kapol.find(1) is correct.