Postgres 15 improves UNIQUE and NULL

Re:Postgres 15 improves UNIQUE and NULL by lmm on Monday July 11, 2022 @09:26PM (#32064461)

SQL absolutely does have that problem. You have no way of enforcing or checking that an expression is supposed to be non-NULL; at best you get an error at runtime when you try to insert it into a given column, which is usually far too late.

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Re:Postgres 15 improves UNIQUE and NULL by anamexis on Tuesday July 12, 2022 @09:32AM (#32069645)

This is only a problem insofar as any data constraint is a problem.

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Re:Postgres 15 improves UNIQUE and NULL by lmm on Tuesday July 12, 2022 @05:53PM (#32076173)

No, it's a specific problem of SQL that you can apply constraints to stored or quasistored columns but not to expressions. In a real typed language every expression has a type.

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