Object-relational mapping

Libraries that map SQL database tables and rows to Ruby classes and objects in order to enable easy interaction with the data persistence layer from your program

A long-lived project that still receives updates
Databases on Rails. Build a persistent domain model by mapping database tables to Ruby classes. Strong conventions for associations, validations, aggregations, migrations, and testing come baked-in.
No release in over 3 years
Low commit activity in last 3 years
Squeel unlocks the power of Arel in your Rails application with a handy block-based syntax. You can write subqueries, access named functions provided by your RDBMS, and more, all without writing SQL strings. Supporting Rails 3 and 4.
No release in over 3 years
Object Graph (Og) is a state of the art ORM system. Og serializes standard Ruby objects to Mysql, Postgres, Sqlite, KirbyBase, Filesystem and more.