What problem does it solve? Designing a data layer without a clear access pattern leads to schemas that need expensive rework, N+1 query traps, unsafe migrations that lock production tables, and caches with no invalidation plan. This Skill provides design-time guidance for Postgres, MySQL/MariaDB, Prisma, Redis, and JPA so the data layer is shaped correctly before any code exists to review. ## Core Features & Use Cases - Schema and ORM design: Postgres and MySQL/MariaDB schema defaults, indexing strategy, Prisma connection pooling and N+1 avoidance, and JPA entity/fetch/transaction design. - Caching and queue strategy: Redis data structure selection, TTL guidance, cache invalidation patterns (TTL, tag-based, write-through), and Redis Streams vs dedicated queue trade-offs. - Safe migration sequencing: Cross-ORM expand-contract pattern, batched backfills, concurrent index creation, and reversibility requirements for zero-downtime schema changes. - Use Case: When asked "design a schema for a marketplace orders feature", the Skill first establishes the access patterns, then produces a schema with correct indexes, a Prisma or JPA setup, and an expand-contract migration plan that a later code review will not flag. ## Quick Start Ask the assistant to design a Postgres schema and Prisma setup for a new feature, including a safe migration strategy and Redis caching plan.
