Re: DBI-Bind parameters

On Thu, 2007-08-23 at 10:17 +0800, Ow Mun Heng wrote:
Current method.. pseudo code.

while (1)
{
$from_datetime = time;
$to_datetime = time + $time_interval;

$query = "select count(*) from table where time >= ? and time <?";
$sth = $dbh->prepare($query)
$sth->execute($from_datetime, $to_datetime)
$from_datetime = $to_datetime;
}

Results:

1st time ran.. will have results.
2nd and subsequent.. no results.

based on DBI->trace(1)

<- prepare('select count(*)
from table(nolock) where time >= ? and time < ?
')= DBI::st=HASH(0x8756294) at mssql_2_postgres_cvs.pl line 236
<- execute('2007-08-22 18:00:00' '2007-08-22 18:01:00')= -1 at
mssql_2_postgres_cvs.pl line 238
<- fetchrow_array= ( 103 ) [1 items] row1 at mssql_2_postgres_cvs.pl
line 247
"103"


2nd subsequent queries
<- DESTROY(DBI::st=HASH(8720c4c))= undef at mssql_2_postgres_cvs.pl line
238
<- DESTROY(DBI::db=HASH(8755fd0))= undef at mssql_2_postgres_cvs.pl line
238
!! ERROR: -1 'called with 2 bind variables when 4 are needed' (err#0)
<- execute('2007-08-22 18:01:00' '2007-08-22 18:02:00')= undef at
mssql_2_postgres_cvs.pl line 238

If I don't bind the columns, and use

$query = "select count(*) from table where time >= $from_datetime and
time < $to_datetime";

It works for all loops..

so... how come it says 4 bind variables are needed?

I managed to solve it using bind_param..

eg:
$sth->bind_param(1, $from_datetime);
$sth->bind_param(2, $to_datetime);
$sth->execute();
Why is that the above works and the org method doesnt? Anyone knows?



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