Mysql automatically updating foreign keys

In a relational database, redundancies are eliminated — a particular item of information is located at precisely one location, and is linked (joined) to all uses of that item.But the links are references, not copies, which means if the original item needs updating or is found to be in error, only one change needs to be made, and all the uses for that datum change automatically.From a practical standpoint, what this means is that the task of classification now has the absolute minimum of complexity — one species: one table entry — and all uses of that information automatically follow.To be more specific, the user of such a database would begin at the leftmost category and choose the desired entry, then move to the right, gradually focusing in on a particular species, allowing the relational database to assist in the process and eliminate errors: Also, although less efficiently, using such a system a person could enter a species — the rightmost tier of the taxonomic hierarchy — and let the database engine complete the identification automatically.

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Until recently such an arrangement was dearly wished for but not practical.

But with a hierarchical database design based on relational principles, a hierarchy with a degree greater than my simplified diagram is possible, that can strictly relate Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

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