Re: Idea: Avoid JOINs by using path expressions to follow FKs
| От | Isaac Morland |
|---|---|
| Тема | Re: Idea: Avoid JOINs by using path expressions to follow FKs |
| Дата | |
| Msg-id | CAMsGm5eeDXFX7oA9H6hF0E+aZZP4D8nbChtt_3BSotGPLXshNQ@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Idea: Avoid JOINs by using path expressions to follow FKs ("Joel Jacobson" <joel@compiler.org>) |
| Ответы |
Re: Idea: Avoid JOINs by using path expressions to follow FKs
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| Список | pgsql-hackers |
On Tue, 30 Mar 2021 at 15:33, Joel Jacobson <joel@compiler.org> wrote:
Also, should the join be a left join, which would therefore return a NULL when there is no matching record? Or could we have a variation such as ->? to give a left join (NULL when no matching record) with -> using an inner join (record is not included in result when no matching record).Interesting idea, but I think we can keep it simple, and still support the case you mention:If we only have -> and you want to exclude records where the column is NULL (i.e. INNER JOIN),I think we should just use the WHERE clause and filter on such condition.
Just to be clear, it will always be a left join? Agreed that getting the inner join behaviour can be done in the WHERE clause. I think this is a case where simple is good. As long as the left join case is supported I'm happy.
Thanks for the encouraging words. I have exactly the same experience myself and share your view.I look forward to continued discussion on this matter.
I had another idea: maybe the default name of a foreign key constraint to a primary key should simply be the name of the target table? That is, if I say:
FOREIGN KEY (...) REFERENCES t
... then unless the table name t is already in use as a constraint name, it will be used as the constraint name. It would be nice not to have to keep repeating, like this:
CONSTRAINT t FOREIGN KEY (...) REFERENCES t
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