mysql_affected_rows() returns -100

Question

I am getting a very funny problem with my code. Basically the first time when I run the code I get the correct result from the mysqli_effected_rows() function. But the second time I run the same script it keeps giving me "-100"

If I delete all the records in the table and run the code again I get the correct result from mysqli_effected_rows() function.

is "-100" an error code ?

$count ="";

foreach($database as $key=>$value) {

  foreach($value as $field => $cell){

    if ($field =='itemid') {
        echo "the item id is $cell <br />";
        $col1 = $cell ;
    }
    elseif ($field =='title') {

        echo "the title is $cell<br />";
        $col2 = $cell;
    }
    elseif ($field =='starttime') {

        echo "the start time is $cell<br />";
        $col3 = $cell;
    }
  }
  $dbquery = "INSERT INTO cordless_drill(itemid,title,starttime) VALUES ('$col1','$col2','$col3')";
mysqli_query($dbc,$dbquery);

  $count += mysqli_affected_rows($dbc);
}
echo $count ;

Answer 1

Get the number of affected rows by the last INSERT , UPDATE , REPLACE or DELETE query associated with link_identifier . The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If no connection is found or established, an E_WARNING level error is generated. Returns the number of affected rows on success, and -1 if the last query failed. Before attempting $count += mysqli_affected_rows($dbc); just try to echo the values of mysqli_affected_rows($dbc) ... and check any warning occurs ....