Re: UPDATE OR REPLACE?
От | dandl |
---|---|
Тема | Re: UPDATE OR REPLACE? |
Дата | |
Msg-id | 003301d20528$54c282b0$fe478810$@andl.org обсуждение исходный текст |
Ответ на | Re: UPDATE OR REPLACE? (Adrian Klaver <adrian.klaver@aklaver.com>) |
Список | pgsql-general |
> >>> In my particular situation the case I care about is when the > result > >> of an UPDATE is two identical rows. All I really want is a DISTINCT > >> option. > >> > >> Assuming I am following correctly what you want is that the result > of > >> an UPDATE not be two identical rows. > > > > Correct. In practice I don't care whether the action is IGNORE or > REPLACE (in Sqlite terms), the outcome is the same. > > It is not: > https://www.sqlite.org/lang_conflict.html > > > > > Obviously two different records that share the same primary key is a > bad thing and worth an error. Two identical records is just boring. > > I do not see how the Sqlite mechanism achieves that. It only looks at > UNIQUE, NOT NULL, CHECK, and PRIMARY KEY constraints. It is not > looking at the record in its entirety. True: a 'distinct' option is lacking. So for this purpose I use a uniqueness constraint on the whole row. Regards David M Bennett FACS Andl - A New Database Language - andl.org
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