Обсуждение: ECPG and Curors.

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I'm looking at the documentation for Postgresql in Chapter 30 and I'm
checking out how to use FETCH INTO and CURSORs to loop through multiple
results from a table.

In the documentation they show something like

EXEC SQL DECLARE foo CURSOR for select a,b,c from test_table

do {
EXEC SQL FETCH NEXT FROM foo INTO ....

} while ( ... );

what I don't see is how to detect that I've fetched the last row from a
query.   Is there more complete doco on this process somewhere?



- --
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Peter L. Berghold                                     Peter@Berghold.Net
"Those who fail to learn from history are condemned to repeat it."
AIM: redcowdawg        Yahoo IM: blue_cowdawg              ICQ: 11455958
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On Mon, Jun 12, 2006 at 11:14:24PM -0400, Peter L. Berghold wrote:
> what I don't see is how to detect that I've fetched the last row from a
> query.   Is there more complete doco on this process somewhere?

Just look for "exec sql whenever not found ..."

Michael

--
Michael Meskes
Email: Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
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On Mon, Jun 12, 2006 at 11:14:24PM -0400, Peter L. Berghold wrote:
> what I don't see is how to detect that I've fetched the last row from a
> query.   Is there more complete doco on this process somewhere?

You could either handle a NOT FOUND exception, or make use of SQLCODE or
SQLSTATE like this...


EXEC SQL DECLARE csr_fred CURSOR FOR SELECT....

EXEC SQL OPEN csr_fred;

while (SQLCODE == 0) {
    EXEC SQL FETCH csr_fred INTO :jim, :sheila,...

    if (SQLCODE == 0) {

        ....
        body of row processing here
        ....
    }
}

EXEC SQL CLOSE csr_fred;