Original link: https://www.lifengdi.com/archives/transport/technology/3917
To sum up this improvement in one sentence: Support unique constraints and indexes treat null values as the same value. Instead of indexing null values into distinct values, you can now treat null values as the same value by creating a constraint using unique nulls not distinct. Create an example table in two unique styles: CREATE TABLE null_old_style ( id BIGINT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY, val1 TEXT NOT NULL, val2 TEXT NULL, CONSTRAINT u […]
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