esempio di modifica delle guide di colonna
def change
change_column(:table_name, :column_name, :new_type)
end
come creare binari di migrazione
rails g migration AddPartNumberToProducts
activerecord aggiungi colonna
class AddPartNumberToProducts < ActiveRecord::Migration[6.0]
def change
add_column :products, :part_number, :string
end
end
ruby on rails db migrate
rails db:migrate
come creare una tabella SQL in ruby
def self.create_table
sql = <<-SQL
CREATE TABLE IF NOT EXISTS IF NOT EXISTS students (
name TEXT,
grade TEXT
)
SQL
DB[:conn].execute(sql)
end