Re: Getting the results columns before execution
От | Darko Prenosil |
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Тема | Re: Getting the results columns before execution |
Дата | |
Msg-id | 200401191548.16865.darko.prenosil@finteh.hr обсуждение исходный текст |
Ответ на | Getting the results columns before execution (Shachar Shemesh <psql@shemesh.biz>) |
Список | pgsql-hackers |
On Monday 19 January 2004 15:13, Shachar Shemesh wrote: > Hi all, > > From the OLE DB manual: > > The consumer can also get information about the columns of the rowset > > by calling IColumnsInfo::GetColumnInfo, which all providers must > > support, or IColumnsRowset::GetColumnsRowset, which providers may > > support, on the command. > > > > Before calling GetColumnInfo or GetColumnsRowset, the consumer must > > set the command text and, if the provider supports command > > preparation, prepare the command object. > > The problem - it appears there is no requirement to execute the command > before asking about the rowset returned. Only setting the actual command > and preparing it. This is a problem, as merely preparing a command is > not enough to get the returned rows information. > > I'm wondering whether anyone on this list(s) have an idea how to solve > this? I can start the command in a cursor, and not retrieve information > until requested. I can also execute the command with "where 0" appended > to it. Neither solutions seem very practical or good performance wise. > > Shachar LIMIT 0 will do ? I do it often when I need to know structure of the result without returning any rows. Regards !
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