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05.24.2008 at 10:17AM PDT, ID: 23429963
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9.3

Using fetchrow_hashref, how do I tell the difference between no data returned,vs. an error?

Asked by StevenMiles in MySQL Server

Hi,
I make a call to fetchrow_hashref:

first,
$dbh = DBI->connect (... etc

then,
$sth = $dbh->prepare ("SELECT * FROM all_users WHERE $SelectString");
$sth -> execute();

finally,
$hash_ref = $sth->fetchrow_hashref;

Now at this point, I'm not sure how to tell the difference between the case where an error occurred in the processing of fetchrow_hashref, or if on the other hand there simply was no data to return from the SELECT statement.

Here's what I'm doing:
if (!defined($hash_ref)) {
        # No data was returned, or there was an error
        if (defined($dbh->errstr)) {
                # Case where there was an error.
                # Do some error processing here
        }
        else {
                # No error.
                # Case where simply no data was returned
                # Proceed with no data.  No error processing needed
        }
}

I'm such a newbie at MySQL, I don't know whether that code is laughable.  Is there a better way to tell the difference?  And is $dbh->errstr the right thing to test?  Is there such a thing as $sth->errstr.

I think I'm close to the answer, but any help is appreciated.
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[+][-]05.24.2008 at 12:48PM PDT, ID: 21640083

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About this solution

Zone: MySQL Server
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Solution Provided By: shanikawm
Participating Experts: 2
Solution Grade: A
 
 
[+][-]05.24.2008 at 12:54PM PDT, ID: 21640092

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