{"slug":"sql-databases","sectionId":"data-foundations","title":"SQL and databases","summary":"Relational querying, indexing, transactions, OLTP/OLAP modeling, and vector search basics.","focus":["joins and window functions","indexes and explain plans","transactions","pgvector and ANN"],"featureIdea":"Query-plan visualizer for joins, windows, indexes, and vector search.","status":"shell","requiresBackend":true,"tags":["sql","postgresql","vector-search"],"locale":"en","sectionTitle":"Data Foundations","statusLabel":"shell","backendLabel":"backend needed later","pagePath":"/learn/sql-databases","apiPath":"/api/learning/sql-databases","selfCheck":["What is the core job of \"SQL and databases\"?","Which common mistake would break a production implementation of this topic?","Which inputs or limits must be validated before the interactive feature ships?","What is the smallest test that proves the future implementation behaves correctly?","When does this module really need backend compute, and when is a UI simulation enough?"],"implementationNotes":["Start with one focused feature, not a full course inside one page.","All public inputs must be typed, bounded, and covered by reject-case tests.","If a model, dataset, or job is added, document source, license, limits, and fallback.","The interaction must explain the topic rather than serve as decoration."]}