Antipattern: Spaghetti SQL

The smell

• The same business concept ("published, recent posts") expressed slightly differently across many call sites
• where("...") strings in controllers and views
• find_by_sql and raw connection.execute outside of migrations

Why it hurts

• A schema or business-rule change requires hunting every call site
• Easy to drift (one place forgets featured, another forgets a tenancy filter)
• SQL fragments bypass scopes, joins, and security/tenancy filters
• Test setup mirrors the SQL instead of the intent

The fix

• Push every query into a named scope or class method on the model
• Name scopes for the business term, not SQL: published, featured, recent, reverse_chronologically
• For complex queries that don't compose, use a query object PORO (PostsForFeed)
• Call sites read like sentences: Post.published.featured.recent.limit(10)