Re: SQL99 IGNORE
От | Jeff Davis |
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Тема | Re: SQL99 IGNORE |
Дата | |
Msg-id | 1076823979.23097.8.camel@jeff обсуждение исходный текст |
Ответ на | Re: SQL99 IGNORE (Stephan Szabo <sszabo@megazone.bigpanda.com>) |
Ответы |
Re: SQL99 IGNORE
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Список | pgsql-general |
> > I notice that postgres does not support IGNORE. > > > > I am currently migrating an app from a MySQL datastore to Postgres, and I > > would really like to use IGNORE. > > > > I am curious if there is a recommended work-araound. > > What does it do? All I find in SQL99 Part 2 related to the word is that > it's reserved. > If you insert from one table into another via a subselect, there's the possibility that you may violate a unique contraint, simply because many rows are being inserted at once. The IGNORE keyword tells MySQL to simply ignore the duplicates if they exist, not throw an error, and continue inserting the distinct, new records. Of course, there are much more logical ways of avoiding that problem, like simply using a NOT IN on the subquery, or a NOT EXISTS, or maybe even rethink the schema. So, it surprises me that IGNORE is part of the spec, if it is. I don't think I've ever run into a problem where something like this would fit. Regards, Jeff
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