When relational databases RDBs appeared there was a deal of confusion about what they were. Everybody now knows that they are only a collection of very simple records in cardindexed files, where anything is automatically crossreferenced to everything else, but as late as 1986 I had to explain to the MD of a software house that his product was not relational even though it allowed crossreferences to be built between files. Relational databases provide automatic crossreferencing and keep it up to date. They also check it is not selfcontradictory, or in RDB jargon, ensure it has referential integrity.
Records Management Journal – Emerald Publishing
Published: Mar 1, 1991