Re^3: perl and psql

There was a bug in the code that was posted as a reply. I don't think Xilman intended that code to be blindly copy-and-pasted, but here's what's probably going on:

# This should not have the '$dbh->' at the beginning, but the real iss
+ue is
# $cluster here is a scalar, but
foreach my $cluster (@clusters) {
# here, they are being treated as arrays (if they were interpolated as
+ written.
# $dbh->do ("INSERT INTO $table (start, end) VALUES (cluster[0], clust
+er[1]);");
# a better approach, if your DBI module supports placeholders:
$dbh->do ("INSERT INTO $table (start, end) VALUES (?,?);", @{$cluster}
+)
# or even: $dbh->do ("INSERT INTO $table (start, end) VALUES (?,?);", 
+$cluster->[0], $cluster->[1])
}
[download]

Again, this is untested code, and may not work as advertised. If the -> and @{} are confusing you, check out perlreftut for more info on references.

@_=qw;
Just another Perl hacker,;
;$_=q=print
"@_"= and eval;
[download]

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Re^4: perl and psql by almut (Canon) on Dec 02, 2009 at 15:59 UTC
`$dbh->do ("INSERT INTO $table (start, end) VALUES (?,?);", @{$cluster})` When you use do with placeholders and bind values, you also need to specify the `\%attr` hashref (for syntactical reasons, because the synopsis is `$dbh->do($statement, \%attr, @bind_values)`). You may use `undef` if you don't have any attributes. `$dbh->do ("INSERT INTO $table (start, end) VALUES (?,?)", undef, @$clu +ster)` [download]	[reply] [d/l] [select]
Re^4: perl and psql by Xilman (Hermit) on Dec 02, 2009 at 17:11 UTC
Thank you. It was an unfortunate cut&paste error on my part. I'm well aware, of course, that place holders are a Good Idea(tm). The original Perl script from which I made the c&p used them but I removed them from the posted snippet to simplify it. As I said originally, the OP should take my fragment as a hint for a learning exercise and not as a complete answer. Paul	[reply]