Natural versus Surrogate Primary Keys in a Distributed SQL Database
There’s a subtle, but critical, difference between the two notions business-unique key and primary key in a relational database. For example, in a “users” table, the “user_id” could be the primary key while the “email_address” (which must be not null and unique) could be the business-unique key. The columns that implement each notion may or may not coincide. This post shows that,
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