Mementus

Mementus is a transient ORM for creating and querying in-memory object models.

Installation

Add this line to your application's Gemfile and bundle or bundle update:

gem 'mementus'

Or install with your local Rubygems:

$ gem install mementus

Usage

Defining model classes

To define model classes, inherit from the Mementus::Model base class and add attributes using the Virtus API:

class Book < Mementus::Model
  attribute :title, String
  attribute :author, String
end

Creating objects

Create new instances by passing data through the constructor or assigning attributes directly:

book1 = Book.new(
  :title => "Gravity's Rainbow",
  :author => "Thomas Pynchon"
)

book2 = Book.new
book2.title = "The Golden Notebook"
book2.author = "Doris Lessing"

To write objects to the in-memory index, call their create method:

book3 = Book.new(
  :title => "Crash",
  :author => "J.G. Ballard"
)

book3.create

Matching queries

Basic match queries can be constructed by passing a predicate hash to the where method:

Book.where(author: "Doris Lessing")

Book.where(title: "Crash")

Scoped queries

Reusable query shortcuts can be constructed on the model class by defining a scope:

class Book < Mementus::Model
  attribute :title, String
  attribute :author, String
  attribute :genre, String
  scope :scifi, genre: 'scifi'
  scope :romance, genre: 'romance'
end 

These defined scopes become class methods on the model:

scifi_books = Book.scifi
romance_books = Book.romance

Roadmap

• 0.2: Query API
• 0.3: Relationships API
• 0.4: Value objects

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request