Database Engineering
Relational Modeling
Turning requirements into tables: entities, relationships, keys, constraints — and the access patterns that decide all of it.
From Requirements to Tables
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A schema is derived from access patterns, not from nouns: list the questions the system must answer and how often, then design the tables and indexes that answer the frequent ones cheaply.
Relationships, Keys and Constraints
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1-1, 1-N and N-M are implemented with exactly three mechanisms — a foreign key, a unique foreign key, and a junction table — and the choice between natural and surrogate keys is about what may change.