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Joined 5 天前
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Cake day: 2025年2月15日

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  • Having never seen the database schema myself, my read is that the SSN is used as a primary key in one table, and many other tables likely use that as a foreign key. He probably doesn’t understand that foreign keys are used as links and should not be de-duplicated, as that breaks the key relationship in a relational database. As others have mentioned, even in the main table there are probably reused or updated SSNs that would then be multiple rows that have timestamps and/or Boolean flags for current/expired.