Term Kind Topic What it is
Foreign Key Constraint concept Relational Modelling A database-enforced rule that a referencing value must exist in the referenced table — referential integrity that no application bug can violate.
Normalisation Normal Forms practice Relational Modelling Organising a schema so each fact is stored exactly once, removing the update anomalies that duplication creates.
Relational Modelling practice Relational Modelling Designing a schema around entities, relationships and enforced constraints — still the correct default for most transactional systems.
Surrogate Key Synthetic Key concept Relational Modelling A system-generated identifier with no business meaning, used as the primary key instead of a naturally occurring business value.