rails-query-object

Query objects encapsulate complex Rails queries by accepting a user or account context via the constructor, returning an ActiveRecord::Relation or Hash for clean multi-tenant isolation and reusable data access.

A query object in Rails is a dedicated pattern that encapsulates complex multi-table database queries. You should use it for aggregation, report-like scenarios, and multi-tenant isolation to keep business logic testable and clean.

You can test complex ActiveRecord queries using a test-driven workflow with query objects, which isolate multi-table logic and aggregations into reusable classes that accept context like user or account directly through their constructors.

Yes, query objects in Rails can return an ActiveRecord::Relation, allowing you to chain additional methods directly. For aggregation and report-like scenarios, they can also return a Hash instead of a relation.

The best way to organize reusable data access patterns in Rails is using query objects with clear naming conventions. They enforce constructor-based context and return ActiveRecord::Relation or Hash, keeping complex queries maintainable.

Query objects handle aggregations by returning a Hash instead of an ActiveRecord::Relation. This means you cannot chain ActiveRecord methods on Hash results, so you must design your query objects to finalize all needed aggregations internally.