Composite vs Surrogate keys for Referential Integrity in 6NF
Take three layers of information: Layer 1: Information This layer contains data with UNIQUE natural indexes and a surrogate key that is easily transferrable. Table Surnames: +-----------------------------+--------------+ | ID (Auto Increment, PK) | Surname | +-----------------------------+--------------+ | 1 | Smith | | 2 | Edwards | | 3 | Brown | +-----------------------------+--------------+ Table FirstNames +-----------------------------+--------------+ | ID (Auto Increment, PK) | FirstName | +-----------------------------+--------------+ | 1 | John | | 2 | Bob | | 3 | Mary | | 4 | Kate | +