Help needed with variable scoping? or mysql problem

["Mike Klein" <mikeklein@ieee.org>]

I've been using JSP for some time now, and thought I'd write a couple of
rdbms explorers (flat tables, simple master/detail paradigm) using other
technologies, like PHP, Cocoon, etc. Well...it's been fun. I have more
working than not. But now I am hung up. I am getting wierd results in a php
script when I simply change the order of some mysql calls.

I'm using php-4.3.2, rh9, and mysql 3.23.

My error is the following (the first line above the Warning below is a dump
of parameters to the showMaster function which is what's bombing):

conn=Resource id #3 databaseName=info tableName=movies fieldName=title
fieldValue=36th Chamber
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result
resource in /foo/bar/mywebsite/private/database.php on line 107

Line 107 is the <first> mysql_num_rows call below.

function showMaster($conn, $databaseName, $tableName, $fieldName,
$fieldValue)
{
        echo "conn=$conn\n";
        echo "databaseName=$databaseName\n";
        echo "tableName=$tableName\n";
        echo "fieldName=$fieldName\n";
        echo "fieldValue=$fieldValue\n";

        ========This code fails when placed here==========
        $result = mysql_query("SELECT * FROM $tableName where
$fieldName='$fieldValue'", $conn);
        $numRows = mysql_num_rows($result);
        if(mysql_num_rows($result) == 1)
        {
                showDetail($conn, $databaseName, $tableName, $fieldName,
$fieldValue, $result);
                exit;
        }
        echo "numRows=$numRows\n";

        ========================================
        $fields = mysql_list_fields($databaseName, $tableName, $conn);
        $numFields = mysql_num_fields($fields);
        echo "<TABLE border=1 width=100%>\n";
        echo "<tr>";
        for($i = 0; $i < $numFields; $i++)
        {
                printf("<td>%s</td>", mysql_field_name($fields, $i));
        }
        echo "</tr>";

        ========The SAME code succeeds when placed here!!!!!==========
        $result = mysql_query("SELECT * FROM $tableName where
$fieldName='$fieldValue'", $conn);
        $numRows = mysql_num_rows($result);
        if(mysql_num_rows($result) == 1)
        {
                showDetail($conn, $databaseName, $tableName, $fieldName,
$fieldValue, $result);
                exit;
        }
        echo "numRows=$numRows\n";

        ========================================
        while($myrow = mysql_fetch_array($result))
        ...rest of method...
}

Any ideas on why this is? When I move the lines above (from
$result=...to...echo 'numRows') down a few lines to just before the
mysql_fetch_array, then everything works. Whazzup?!?


mike klein



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