database design - MD5 hash as artificial keys -

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i'm seeing lots of applications using hashes surrogate keys instead of plain integers. can't see reason kind of design.

given uuid implementations hashed timestamps, why many database designers choose them application-wide surrogate keys?

if data backend application made out of multiple distributed databases, using incremented integer ids might lead duplicated values. uuids guaranteed unique not inside application outside (which might helpful when joining external data).

it true using different id seeds different databases in system solve uniqueness problem integers, managing such approach more difficult.


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