ActiveRecordLite

Summary

ActiveRecordLite is an ORM that maps SQLite queries onto Ruby objects. It aims to provide an austere, yet full-featured alternative to ActiveRecord without all the overhead.

Demo

Clone the repo
Head into irb or pry
load './demo.rb'
Go wild (using demo.rb as a reference)

Libraries

SQLite3 (gem)
ActiveSupport::Inflector

Features

Replicates core functionality of ActiveRecord::Base and ActiveRecord::Relation (as SQLObject and SQLRelation)
Super friendly API - most SQLObject and SQLRelation enumerative methods will accept params or a block as an argument
SQLRelation search parameters are stackable and lazily-evaluated - i.e. Cat.all.where(name: "Rocco").where(owner_id: 2) won't fire off a SQL query until you call #count, #force, #limit, etc.

API

SQLObject provides a few of your favorite ActiveRecord associations:

has_many
belongs_to
has_one_through

SQLObject provides all your favorite ActiveRecord methods:

::count
::find
::where
::delete_all
::update_all
#save
#create
#update
#destroy

SQLRelation provides all your favorite Enumerable methods:

#<<
#all?
#any?
#count
#empty?
#first
#last
#none?
#one?

SQLObject delegates enumerable methods (along with ::find, ::where, ::delete_all and ::update_all) to SQLRelation. For example, Cat.any? will iterate over the entire cats table and return an SQLRelation instance.

SQLObject utility methods conventionally return an SQLRelation instance as a collection object. This means you can chain methods like so: Cat.where(owner_id: 1).update_all(owner_id: 2).find(1).

How It Works

SQLObject and SQLRelation make reference to DBConnection, which delegates SQLite::Database instance methods like #execute, #get_first_row, #last_insert_row_id, etc. to a singleton instance of SQLite::Database. Consumers of the API specify this instance by calling DBConnection::open(file), providing an SQLite db file path as an argument.

SQLObject and SQLRelation provide a utility belt of class/instance methods that map to SQL queries. You can make use of the SQLObject API by creating a class that inherits from it (see demo.rb for an example).

Associations (has_many, belongs_to, has_one_through) are dynamically generated by the Associatable module, which extends SQLObject. Associations infer class_name, foreign_key and primary_key based on the same conventions as ActiveRecord. You can override these if the database schema you're working with is non-compliant (or ActiveSupport::Inflector fails to guess your table name).

Notes

ActiveSupport::Inflector isn't a hard dependency; it's really only used in has_many, to provide sensible class_name and foreign_key defaults (see above).

If you really want to trim overhead, you can get away with declaring options for these manually in your association definitions.

License

ActiveRecordLite is released under the MIT License.

Developed by Chris Sloop

cribbles / ActiveRecordLite