Re: [INTERFACES] [libpq] Return value of int
От | Henk Jan Barendregt |
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Тема | Re: [INTERFACES] [libpq] Return value of int |
Дата | |
Msg-id | 372C7DA6.3399D65@barendregt.xs4all.nl обсуждение исходный текст |
Ответ на | Re: [INTERFACES] [libpq] Return value of int (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-interfaces |
Tom Lane wrote: > > Henk Jan Barendregt <henkjan@barendregt.xs4all.nl> writes: > > How can i use libpq to return an int value when i access an INT or INT4 > > value > > Use atoi() ... what comes out of libpq is a character string always. > It's up to you to convert it to whatever form you want it in. > > Actually, if you are really intent on avoiding the conversion step > you can use a binary cursor and get the data in whatever the backend's > internal format is. However I can't recommend this. I've found by > measurement that the conversion time is insignificant compared to the > rest of the work involved in a query, even for expensive-to-convert > datatypes like DATETIME. And for that trivial savings you expend a > lot of programming effort: you have to know what the backend's internal > format *is*, and you have to be prepared to deal with cross-machine > compatibility issues (maybe the backend is running on a machine with > different endianness than your app is ... how will you even know?), > cross-Postgres-version changes in the internal representation, yadda > yadda. Much better to take the character string. > > But if you insist on doing it the hard way, read about DECLARE CURSOR > and FETCH in the manual. > > regards, tom lane Thanks a lot for the explanation. It is gave me some good reasons to stay on my path and convert the results to whatever i need. Henk Jan
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