rethinkdb-orm
RethinkDB ORM for Crystal Lang
Extending ActiveModel for attribute definitions, callbacks and validations
Callbacks
Register callbacks for save
, update
, create
and destroy
by setting the corresponding before/after callback handler.
class ModelWithCallbacks < RethinkORM::Base
attribute address : String
attribute age : Int32 = 10
before_create :set_address
after_update :set_age
before_destroy do
self.name = "joe"
end
def set_address
self.address = "23"
end
def set_age
self.age = 30
end
end
Associations
Set associations with belongs_to
, has_many
and has_one
.
Access children in parent by accessing the method correpsonding to the pluralised child. Children collection method name is generated by dumb pluralisation (appending an s). Optionally set children collection name in has_many
by setting collection_name
param.
The has_many
association requires the belongs_to
association on the child. By default, belongs_to
creates a secondary index on the foreign key.
class Parent < RethinkORM::Base
attribute name : String
has_many Child, collection_name: "children"
end
class Child < RethinkORM::Base
attribute age : Int32
belongs_to Parent
has_many Pet
end
class Pet < RethinkORM::Base
attribute name : String
belongs_to Child
end
parent = Parent.new(name: "Phil")
parent.children.empty? # => true
child = Child.new(age: 99)
child.pets.empty? # => true
belongs_to
Parameter | | Default
-------------- | ------------------------------------------------------------- | -------
parent_class
| The parent class who this class is dependent on |
dependent
| Sets destroy behaviour. One of :none
, :destroy
, :delete
| :none
create_index
| Create a secondary index on the foreign key | true
through
| Sets a through relationship | nil
has_many
Parameter | | Default
----------------- | ----------------------------------------------------------------------------- | -------
child_class
| The parent class who this class is dependent on |
dependent
| Sets destroy behaviour. One of :none
, :destroy
, :delete
| :none
collection_name
| Define collection name, otherwise collection named through dumb pluralisation | nil
through
| Sets a through relationship | nil
has_one
Parameter | | Default
----------------- | ----------------------------------------------------------------------------- | -------
child_class
| The parent class who this class is dependent on |
dependent
| Sets destroy behaviour. One of :none
, :destroy
, :delete
| :none
collection_name
| Define collection name, otherwise collection named through dumb pluralisation | nil
through
| Sets a through relationship | nil
Dependency
dependent
param in the association definition macros defines the fate of the association on model destruction.
Default is :none
, :destroy
and :delete
ensure destruction of association dependents.
Through Relation
In progress..
Indexes
Set secondary indexes with secondary_index
Parameter | |
----------- | --------------------------------------------- |
attribute
| defines the field on which to create an index |
Changefeeds
Access the changefeed of a document or table through the changes
query.
Defaults to watch for events on a table if no id provided.
Parameter | | Default
--------- | ----------------------------------- | -------
id
| id of document to watch for changes | nil
Returns an iterator that emits NamedTuple(value: T | Nil, event: Event)
enum Event
Created
Updated
Deleted
end
class Game < RethinkORM::Base
attribute type : String
attribute score : Int32, default: 0
end
ballgame = Game.create!(type: "footy")
# Observe changes on a single document
spawn do
Game.changes(ballgame.id).each do |change|
game = change[:value]
puts "looks like the score is #{game.score}" unless game.nil?
end
end
# Observe changes on a table
spawn do
Game.changes.each do |change|
game = change[:value]
puts "#{game.type}: #{game.score}" unless game.nil?
puts "game event: #{change[:event]}"
end
end