adding two ActiveRecord::Relation objects
30986
Combine two ActiveRecord::Relation objects
125605
How can I get all pairs of values from an association with elements key->list
20657
Postgres : Relation does not exist error
33472
MongoDB relationships: embed or reference?
127793
How can I create an association list from 2 lists?
46432
What is the "N+1 selects problem" in ORM (Object-Relational Mapping)?
72720
How to skip ActiveRecord callbacks?
45949
Is there a simpler way of drawing relation maps?
91452
Rails ActiveRecord conditions
136972
Why can't I create active records that count for something in rspec?
155351
Rails: Has and belongs to many (HABTM) -- create association without creating other records
57466
Reflexive and relation
146176
Rails nested association and restarted numbering
102909
Problem constructing Association tables with some operators
143850
collection_select, undefined method `map' for nil:NilClass
64483
Inserting into related tables
153316
Renaming the created_at, updated_at columns of ActiveRecord/Rails