Relational Database Design

A logical, RDBMS-agnostic method for designing sound relational databases — the decisions a schema forces and how a disciplined logical-design methodology settles them, written so an agent applies them while designing or reviewing a schema. Each rule names a specific wrong default it corrects; there is no rule for things the model already gets right.

The whole method produces the logical structure first — the tables, fields, keys, relationships, and integrity rules an organization's information requires — deliberately independent of any particular RDBMS product or physical/performance concern. Followed faithfully, it yields fully normalized tables without treating normalization as a separate back-end phase.

When to Apply

• Designing a new relational schema from requirements
• Reviewing or refactoring an existing schema for structural soundness
• Resolving repeating groups, multivalued/multipart fields, or redundant data
• Choosing candidate, primary, and foreign keys for a table
• Modeling one-to-one, one-to-many, many-to-many, or self-referencing relationships
• Deciding deletion rules (restrict, cascade, nullify, deny, set default) and participation constraints
• Deciding where a constraint belongs — field spec, relationship, validation table, or application
• Diagnosing a schema that duplicates, loses, or corrupts data

This skill covers logical design. It does not cover SQL dialects, indexing, partitioning, query tuning, or analytical/dimensional (star-schema) modeling — those are physical/implementation concerns handled after the logical design is sound.