https://habr.com/en/companies/postgrespro/articles/443284/ ru editor@habr.com habr.com Sat, 02 May 2026 14:40:23 GMT https://habr.com/ru/ https://habrastorage.org/webt/ym/el/wk/ymelwk3zy1gawz4nkejl_-ammtc.png https://habr.com/en/companies/postgrespro/articles/443284/#comment_21239524 https://habr.com/en/companies/postgrespro/articles/443284/#comment_21239524 Oh. Of course you're right, it was clearly a mistake. I've corrected the text, thank you.

]]> Thu, 06 Feb 2020 10:42:37 GMT https://habr.com/en/companies/postgrespro/articles/443284/#comment_21232960 https://habr.com/en/companies/postgrespro/articles/443284/#comment_21232960 But let's assume that we want to add extra columns needed for a query to the unique index. Values of the new composite key may now fail to be unique

All the way around: If (book_ref) is unique, then (book_ref, book_date) can not be nonunique. What you are trying to say is the opposite: enforcing uniqueness of (book_ref, book_date) is not enough to get uniqueness of (book_ref) (which you want to use for foreign key).
]]> Wed, 05 Feb 2020 08:33:11 GMT https://habr.com/en/companies/postgrespro/articles/443284/#comment_19937790 https://habr.com/en/companies/postgrespro/articles/443284/#comment_19937790 Mon, 25 Mar 2019 09:28:12 GMT https://habr.com/en/companies/postgrespro/articles/443284/#comment_19937444 https://habr.com/en/companies/postgrespro/articles/443284/#comment_19937444 erogov, скажите, а в чём смысл перевода своей статьи на хабре (двухлетней давности) с русского на английский и публикации её заново в русском же хабре?]]> Mon, 25 Mar 2019 08:35:59 GMT https://habr.com/en/companies/postgrespro/articles/443284/#comment_19937438 https://habr.com/en/companies/postgrespro/articles/443284/#comment_19937438 Mon, 25 Mar 2019 08:35:08 GMT