Mongoid

MongoDB is a document-oriented database, perfect for high intensive load environments.

Mongoid is written in Ruby and it offers a familiar API for developers that previously used ORMs like Data Mapper or Active Record.

Because of MongoDB's schemaless, performant document-based design, dynamic queries, and atomic modifier operations, a classic ORM pattern cannot be applied. That's why the term ODM perfectly describes what Monogid is.

What is new in this release:

• Mongoid 4 now only supports MongoDB 2.4.0 and higher.
• Document#metadata has been renamed to Document#relation_metadata to avoid common conflicts. Relation proxies also have this renamed to the same as well.
• Scopes and default scopes must now all be defined within lambdas or procs.
• skip_version_check config option was removed.
• IdentityMap removed.
• Eager load rework. Eager load now doesnt need the identity map to load related documents. A set of preloaders can eager load the associations passed to .includes method.

What is new in version 4.0.2:

• Mongoid 4 now only supports MongoDB 2.4.0 and higher.
• Document#metadata has been renamed to Document#relation_metadata to avoid common conflicts. Relation proxies also have this renamed to the same as well.
• Scopes and default scopes must now all be defined within lambdas or procs.
• skip_version_check config option was removed.
• IdentityMap removed.
• Eager load rework. Eager load now doesnt need the identity map to load related documents. A set of preloaders can eager load the associations passed to .includes method.

What is new in version 3.1.0:

• The minimum MongoDB requirement is now raised to 2.2, since we now depend on the aggregation framework.
• The minimum Active Model and Active Support dependencies have been raised to 3.2.
• Relations can now specify a primary key to use instead of the id on foreign keys.

What is new in version 3.0.0:

• Added an ORM-agnostic way to get the field names
• A setter and getter for has_many relations to set it's children is now provided.
• Mongoid now supports regex fields.
• Polymorphic relations now use *_type keys in lookup queries.
• Objects that respond to to_criteria can now be merged into existing criteria objects.
• Eager loading is now supported on many-to-many relations.
• Mongoid now enables autosave, like Active Record, when adding an accepts_nested_attributes_for to a relation.
• Fields can now be flagged as readonly, which will only let their values be set when the document is new.