dumpable¶ ↑

The situation is all too common. There is an error in production that you want to reproduce in your local development environment. Only problem is that the production environment has database data that you don’t have locally.

So then you generally only have one option: dump your entire production database, or a subset of your production database to a sql file and import the dump into your local database.

What if time is of the essense, and the production database is huge? What if you could dump only the specific records and their associations that you need to reproduce the record causing problems in your local database.

Dumpable allows you to do just that. You can dump single rows (or a collection of rows), and choose which associations to dump with those rows.

Add the following to your Gemfile:

gem 'dumpable'

The dumpable gem will automatically add the class method #dumpable and the instance method #dump into all your ActiveRecord models.

By default, calling dump on any record will output the sql insert statement necessary to create that record. It will not generate the insert statements for any of the record’s associations. These can either be specified class level by calling #dumpable with the set of assocations to dump or a run-time in your call to #dump.

Both cases will be demonstrated below.

class User < ActiveRecord::Base
  has_many :posts
  has_many :roles

  dumpable dumps: [:roles, {:posts => :comments}]
end

class Role < ActiveRecord::Base
  belongs_to :user
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comments < ActiveRecord::Base
  belongs_to :post
end

Then, from the console, you can do something like:

User.first.dump

This will spit out all the MySQL insertion code for the user, it’s roles, it’s posts, and each post’s comments

If you want each record to pad the ids generated in the insertion code, this can be done as follows:

User.first.dump(:id_padding => 1000)

This will ensure that the id of the above user is padded by 1000, so a user id of 1 will generate an insert statement with an id of 1001.

You may wonder why the id is included as part of the insert statement. This is to ensure that all associations maintain their relationship to one another.

All ActiveRecord models are dumpable automatically, so you could also call:

Post.dump
# or
Post.dump(:dumps => :comments)

You can also dump all the entries in the table by calling:

Post.dump
# or with conditions
Post.where(:published => true).dump

User.dump(:file => PATH_TO_FILE)

Dumpable.dump(Post, Comment.limit(10), Role.where(:active => true)) # will output to console
Dumpable.dump(Post, Comment.limit(10), Role.where(:active => true), :file => "dump.sql") # will output to file

At the moment, Dumpable will not work on any complex relationships. This includes has_many :through, and has_and_belongs_to_many. It also will not work on models that have a different primary key than id or on models with complex keys.

It is also only setup to work with MySQL databases and is untested with any other databases.

Copyright © 2013 Andrew Hunter. See LICENSE.txt for further details.