Rails Migration Tips and Examples (not a full step by step)

#migration #ruby #database #generate

Generates the model and migration, but also all of the RCAVs for index, show, create, update, and destroy.

The model name must be singular.
Separate column names and datatypes with colons (NO SPACES).
Separate name:datatype pairs with spaces (NO COMMAS).

rails generate draft:resource <MODEL_NAME_SINGULAR> <COLUMN_1_NAME>:<COLUMN_1_DATATYPE> <COLUMN_2_NAME>:<COLUMN_2_DATATYPE> # etc

EX:
rails generate draft:resource board name:string
        OR
rails generate draft:resource post title:string body:text expires_on:date board_id:integer

Execute the generated migrations with:

rake db:migrate

This will remove all the files that rails generate draft:resource post ... had previously added. You can then correct your error and re-generate from scratch.

rails destroy draft:resource post

If you made a mistake when generating your draft:resource AND you’ve already run rake db:migrate, then first you have to run the command:

rake db:rollback

Adding and Removing columns

Ex:
rails g migration AddImageToPosts
    OR
rails g migration RemoveExpiresOnFromPosts

If your database gets into a weird state (usually caused by deleting old migration files), your ultimate last resort is
This will destroy your entire database and all the data within it. Then, you can fix your migrations and re-run all from scratch with rake db:migrate, then rake sample_data to recover the sample data.