database-design-engineering

# Database Design Engineering Acknowledgement: Shared by Peter Bamuhigire, techguypeter.com, +256 784 464178. <!-- dual-compat-start --> ## Use When - Use when designing or reviewing relational or document-backed data architecture for SaaS platforms, ERP systems, APIs, analytics stores, or mobile sync. Covers domain modeling, tenancy, indexing, migrations, integrity, retention, and performance tradeoffs. ## Do Not Use When - The task is query tuning or production incident diagnosis without a schema-design decision; use the database operations or reliability skill. - The datastore is a search index, cache, or vector store whose source-of-truth semantics belong elsewhere. ## Required Inputs | Input | Required | Why it matters | |---|---|---| | Domain entities, invariants, and lifecycle rules | yes | Determines tables, keys, constraints, and valid state transitions | | Read and write access patterns | yes | Drives indexes, transaction boundaries, and denormalization choices | | Data volume, growth, and retention expectations | yes | Exposes scaling and archival constraints | | Existing schema and migration constraints | conditional | Enables safe evolution without data loss or prolonged locking | ## Workflow Model invariants and ownership, choose keys and relationships, enforce integrity in the database, design indexes from verified access paths, plan reversible expand-contract migrations, then test concurrency, rollback, and representative query plans. ## Quality Stand...