Array handling in libpq
От | Joris van Zwieten |
---|---|
Тема | Array handling in libpq |
Дата | |
Msg-id | 53632.192.87.1.229.1168989191.squirrel@control.prolocation.net обсуждение исходный текст |
Ответы |
Re: Array handling in libpq
|
Список | pgsql-interfaces |
Hi everyone, I've been using postgres for several projects and I must confess I really like it so far. :-) I hope someone on this list could help me out. Suppose I have a table defined with: CREATE TABLE foo(bar double precision[]); My initial guess was that, as postgres supports arrays, there would probably also be some support for this in libpq (which I'm using via libpqxx by the way). However, from what I've been able to find, it seems that if I use the text format for parameters / results, I would have to: 1. [SEND] Convert the double array on the C(++) side to a '{}' delimited string representation. 2. [RECV] Convert something like '{3.124, 4.5234, 123.123}' to a C(++) array of doubles myself. I hope I overlooked something and there is some support for sending / receiving (parsing) arrays in libpq?? That would be a big help. Still, sending double in ASCII does not seem that efficient. It's not a trivial conversion and it takes more bytes than sending it as binary. However, it seems that using the binary format, I would have to: 1. [SEND] Convert to network byte order Send the array in the format arrayfuncs.c::array_recv() expects, i.e. including the right header (and a length per element as well). 2. [RECV] Parse the header, and convert from byte order Am I missing something here? Or is this just the way it is? (Which is also fine, then at least I know what I'm up against... ;-) Thanks, Joris van Zwieten
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