ActiveRecord & Databases in Rails

ActiveRecord is Rails' Object Relational Mapping system. It allows you to define Ruby classes that represent tables in your database so you can create, query, edit, and delete records and their associations. It also provides a home for business logic so you can define and run operations against your database. In this series, we'll teach you how to use ActiveRecord in your Rails apps.

Start Series

30m

13 Lessons | 3h 39m | Intermediate

30m

Fixing Counter Caches in the Paranoia Gem

Mar 13, 2017 Pro

A walk through of the process of fixing a popular gem and learning how ActiveRecord and the Paranoia gem works

21m

Advanced Counter Caching

Mar 07, 2017 Pro

Add advanced counter caching for soft deletable models, scopes, and has_many relationships

Virtual Generated Columns in Rails with ActiveRecord

Sep 06, 2023 Pro

Rails' ActiveRecord supports virtual generated columns in the database. For example, you can use these for converting numbers like degrees Celsius to Fahrenheit. These columns are saved with the regular table data and allows you to query against them.

Strict Loading with ActiveRecord

Oct 16, 2023 Pro

Not eager loading in your Rails applications can have series performance side effects. Rails now comes with a strict_loading feature that you can use to make sure that queries are run in an efficient manner.

19m

Custom Attribute Serializers with ActiveRecord in Rails

Nov 13, 2023 Pro

Did you know serialize can be used for more than saving Ruby hashes as JSON or Yaml in your db? You can take any attribute and convert it to an object seamlessly with Rails using serialize and custom coders.

13m

Single Table Inheritance (STI) with ActiveRecord in Rails

Jan 22, 2024

Have models that store the same data but need different functionality? Rails provides Single Table Inheritance in ActiveRecord to solve this problem.

15m

Dynamic Single Table Inheritance with Rails

Jan 29, 2024 Pro

Using some Ruby metaprogramming and class_eval, we can build Notifiers that allow us to dynamically define STI models and inject code into them with our notification system.

Extending Rails Associations with Custom Features

Feb 19, 2024 Pro

Rails associations provide an object that quacks like an ActiveRecord but is actually a CollectionProxy. We can extend the proxy object with our own functionality to add useful features with Ruby Modules.