Re: MERGE Specification
От | Simon Riggs |
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Тема | Re: MERGE Specification |
Дата | |
Msg-id | 1281081202.1838.2527.camel@ebony обсуждение исходный текст |
Ответ на | Re: MERGE Specification (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>) |
Ответы |
Re: MERGE Specification
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Список | pgsql-hackers |
On Fri, 2010-08-06 at 10:28 +0300, Heikki Linnakangas wrote: > On 06/08/10 10:12, Simon Riggs wrote: > > So DO NOTHING is the default and implies silently ignoring rows. RAISE > > ERROR is the opposite. > > > > Coding for those seems very easy, its just a question of "should we do > > it?". DB2 has it; SQL:2008 does not. But then SQL:2008 followed the DB2 > > introduction of AND clauses, and SQL:2011 has so far followed the DB2 > > introduction of DELETE action also. > > I see neither DO NOTHING or RAISE ERROR in the documentation of DB2, > Oracle, or MSSQL server. Agreed, Oracle and MSSQL server does not have these. However, DB2 very clearly does have these features * SIGNAL which raises an error and can be used in place of any action, at any point in sequence of WHEN clauses. DB2 already supports SIGNAL as part of SQL/PSM, which we do not, so RAISE ERROR was the nearest equivalent command for PostgreSQL. * ELSE IGNORE which does same thing as DO NOTHING, except it must always be last statement in a sequence of WHEN clauses. DO NOTHING is already a phrase with exactly this meaning in PostgreSQL, so I suggest that. -- Simon Riggs www.2ndQuadrant.comPostgreSQL Development, 24x7 Support, Training and Services
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