Episode #001

#001 · 21 September 2026 · 5:02 rails uniqueness validationvalidates uniqueness railsrails normalizesrails unique indexrails duplicate recordsrails race conditionactiverecord validationsrails model validationsrails form errorspostgres unique indexpostgresql constraintsdata integrityrails 8activerecordruby on rails tutorialruby on railspostgresweb development

Your Rails uniqueness validation won't stop duplicates

After this episode the viewer can stop bad data at the model with validates and normalizes, show the errors in the form, and back the rule with a database index.

Prerequisites: demo-shop on episode-001-before, Rails 8.1

Not covered: tests, custom error messages, client-side validation, i18n

Source: https://github.com/webmatze/demo-shop (branches: episode-001-before / episode-001-after)

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5:02 NOW PLAYING

#00121 Sep 2026rails uniqueness validation · validates uniqueness rails · rails normalizes · rails unique index · rails duplicate records · rails race condition · activerecord validations · rails model validations · rails form errors · postgres unique index · postgresql constraints · data integrity · rails 8 · activerecord · ruby on rails tutorial · ruby on rails · postgres · web development

Your Rails uniqueness validation won't stop duplicates

After this episode the viewer can stop bad data at the model with validates and normalizes, show the errors in the form, and back the rule with a database index.