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Message-ID: <8ec76080812090936g596abf91jdd8a184c3f56c32@mail.gmail.com>
Date: Tue, 9 Dec 2008 12:36:35 -0500
From: "Whit Armstrong" <armstrong.whit@gmail.com>
To: "Jeroen Vermeulen" <jtv@xs4all.nl>
Subject: Re: simple example of copying data from a c/c++ array into postgres
Cc: pgsql-interfaces@postgresql.org
In-Reply-To: <493EA271.8010209@xs4all.nl>
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References: <8ec76080812090708g93000f9l7e7f3e2162587331@mail.gmail.com>
	<493EA271.8010209@xs4all.nl>

Thanks, Jeroen,

I've used copy before from the prompt.  Thanks for alerting me to the
psql functions for it.

can copy be used to append data to a table?

The only reason I'm hesitant to use the copy command is because I
would have to render every row of my data to a string, and 64bit
doubles could mean long strings, formating issues, etc.

roughly what I was thinking was (this is pseudocode):

PGtuple myTuple = createTuple();
myTuple.push_back(toPGDate(myDate));
myTuple.push_back(toPGDouble(myDouble));
etc...

PGinsert_tuple(conn, myDestinationTable, myTuple);

are there facilities to do something like that, or am I really reaching here?

Thanks,
Whit


On Tue, Dec 9, 2008 at 11:53 AM, Jeroen Vermeulen <jtv@xs4all.nl> wrote:
> Whit Armstrong wrote:
>>
>> would someone mind showing me an example of making an insert from binary
>> data to postgres?
>
> Not an example, but have a look at the COPY command:
>
> http://www.postgresql.org/docs/8.3/interactive/sql-copy.html
>
> COPY FROM stdin lets you insert data in bulk, without having to issue a new
> INSERT for every row.  There are some handy libpq functions for feeding data
> into this mechanism:
>
> http://www.postgresql.org/docs/8.3/interactive/libpq-copy.html
>
> The "binary" part of what you're asking for is also possible, but probably
> doesn't buy you all that much.  Chances are you'd need to do some
> conversions anyway, and it introduces all sorts of maintenance risk for an
> optimization that's not likely to matter as much as disk flushes, network
> transfers etc.
>
>
> Jeroen
>