Ruby / Sequel ORM / Plugins

Plugin: Schema

Adds backwards compatibility for Model.set_schema and Model.create_table.

Sequel's built in schema plugin allows you to define your schema directly in the model using Model.set_schema (which takes a block similar to Database#create_table), and use Model.create_table to create a table using the schema information.

This plugin is mostly suited to test code. If there is any chance that your application's schema could change, you should be using the migration extension instead.

Usage:

# Add the schema methods to all model subclasses (called before loading subclasses)
Sequel::Model.plugin :schema

 # Add the schema methods to the Album class
Album.plugin :schema

Plugin: ValidationHelpers

The validation_helpers plugin contains instance method equivalents for most of the legacy class-level validations. The names and APIs are different, though. Example:

# Add the validation helpers to all model subclasses (called before loading subclasses)
Sequel::Model.plugin :validation_helpers

class Album < Sequel::Model
  def validate
    super  # NB! calling `super` first
    validates_min_length 1, :num_tracks
  end
end

See Validations for more info

Plugin: Timestamp

# affect all models
Sequel::Model.plugin(:timestamps)

 # only one model
class Post < Sequel::Model
  plugin :timestamps
end

Plugin: List

Plugin: Tree

Plugin: Paranoid

A plugin for the Ruby ORM Sequel, that allows soft deletion of database entries.

Basics

In order to use the paranoid plugin in the very basic version, just add it your model like this:

# affect all models
Sequel::Model.plugin(:paranoid)

 # affects only one model
class Post < Sequel::Model
  plugin :paranoid
end

This will assume that you have a column deleted_at, which gets filled with the current timestamp once the model gets destroyed:

instance = ParanoidModel.create(:something)

instance.deleted?   # => false
instance.deleted_at # => nil

instance.destroy

instance.deleted?   # => true
instance.deleted_at # => current timestamp

Reading the data

By default the plugin will not change the way scopes have been working.

So if you want to take the deletion state of an entry into account you can use the following dataset filters:

ParanoidModel.present.all      # => Will return all the non-deleted entries from the db.
ParanoidModel.deleted.all      # => Will return all the deleted entries from the db.
ParanoidModel.with_deleted.all # => Will ignore the deletion state (and is the default).

Renaming the deletion timestamp columns

If you don't want to use the default column name deleted_at, you can easily rename that column:

class ParanoidModel < Sequel::Model
  plugin :paranoid, :deleted_at_field_name => :destroyed_at
end

instance = ParanoidModel.create(:something => 'foo')

instance.destroy
instance.destroyed_at # => current timestamp

Enabling the non-deleted default scope

In order to exclude deleted entries by default from any query, you can enable an option in the plugin. One major reason for don't enabling it by default is the fact, that associations are kinda broken, when you want to load also deleted associated instances:

class ParanoidModel < Sequel::Model
  plugin :paranoid, :enable_default_scope => true
  one_to_many :child_models
end

class AnotherModel < Sequel::Model
  plugin :paranoid
  many_to_one :paranoid_model
end

 # create some dummy data

parent1 = ParanoidModel.create(:something => 'foo')
parent2 = ParanoidModel.create(:something => 'bar')

child1  = AnotherModel.create(:something => 'foo')
child2  = AnotherModel.create(:something => 'bar')
child3  = AnotherModel.create(:something => 'baz')

parent1.add_child_model(child1)
parent1.add_child_model(child2)
parent2.add_child_model(child3)

 # destroy one of the children

child1.destroy
child1.deleted? # => true

 # load the children

ChildModel.all                              # => [child2, child3] (works as expected)
ChildModel.dataset.unfiltered.all           # => [child1, child2, child3] (works as expected)

parent1.child_models_dataset.all            # => [child2] (works as expected)
parent1.child_models_dataset.unfiltered.all # => [child1, child2, child3] (broken)

Note that the last command is broken, as child3 is not associated with parent1. The reason for that is unfiltered, which will not only remove the deleted_at check but also the association condition of the query.

Plugin: JSON Serializer

Add JSON output capability to all model instances

# affect all models
Sequel::Model.plugin(:json_serializer)

 # affects only one model
class Post < Sequel::Model
  plugin :json_serializer
end

Plugin: XML Serializer

Add XML output capability to all model instances

# affect all models
Sequel::Model.plugin(:xml_serializer)

 # only one model
class Post < Sequel::Model
  plugin :xml_serializer
end