rake db:reset 

它通过迁移来重新创建表。

It recreates your table from migrations.

如注释中所建议，这是一种更快的方法（但您必须添加一个新的rake任务）是：

As suggested in the comments, a faster way to do it (but you have to add a new rake task) is:

namespace :db do
  desc "Truncate all tables"
  task :truncate => :environment do
    conn = ActiveRecord::Base.connection
    tables = conn.execute("show tables").map { |r| r[0] }
    tables.delete "schema_migrations"
    tables.each { |t| conn.execute("TRUNCATE #{t}") }
  end
end

从以下地址复制的响应：对SO的回答。

Response copied from: answer on SO.