Re: Feature Proposal: Column-Level DELETE Operation in SQL
От | Nico Williams |
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Тема | Re: Feature Proposal: Column-Level DELETE Operation in SQL |
Дата | |
Msg-id | aAk5+zyZ9ztVOi7F@ubby обсуждение исходный текст |
Ответ на | Feature Proposal: Column-Level DELETE Operation in SQL (Abhishek Hatgine <hatgineabhishek99@gmail.com>) |
Список | pgsql-general |
On Mon, Apr 21, 2025 at 10:23:30PM +0530, Abhishek Hatgine wrote: > These would act as a shortcut or expressive alias for setting one or more > column values to NULL. NULL values are not quite no-values, and setting some column of some row to NULL is not quite the same as deleting the column from the row. Even if the database's row encoding is such that a "null value" is not written there will be bits that indicate that the column's value is null. Now in an entity-attribute-value (EAV) sort of schema setting a column to NULL could be made to be the same as deleting that one row. But PG does not currently map tables to EAV stores, though I suppose it could eventually have table types that do just that, but that doesn't mean PG would need a new statement type. Even an RDBMS that only used an EAV metaschema internally would not need a new statement type. Setting a column value to NULL is just not "deleting a colun value". Having two ways to do this doesn't seem necessary at all. Moreover, with UPDATE one can set some columns to NULL values and others to non-NULL values in the same statement, whereas one could not do that with the new statement type you propose. [At this point this is just piling on, for which my apologies, but I thought the EAV thing might be worth noting.] Nico --
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