/************************************************************************
 * deletes an instance of a data                                        *
 ************************************************************************/
function data_delete_instance($id) {    // takes the dataid

    global $CFG;
    if (! $data = get_record('data', 'id', $id)) {
        return false;
    }

/// Print the page header
    $strdata = get_string('modulenameplural','data');
   
    print_header_simple($data->name);
    print_heading(format_string($data->name));

    // This operation could take time to complete...
    @set_time_limit(0);
    // Delete all the associated information
    // Get all the records in this data
    $sql = 'SELECT id FROM '.$CFG->prefix.'data_records WHERE dataid = '.$id;

    if ($records = get_records_sql($sql)) {
        foreach($records as $record) {
            // get all the fields in this record
            $sql = 'SELECT id,fieldid,recordid FROM '.$CFG->prefix.'data_content WHERE recordid = '.$record->id;
            $fields = get_records_sql($sql);

            foreach($fields as $field) {

                // get the field type
                $fieldType = get_record('data_fields','id',$field->fieldid);
                // create a new object to get delete_content_files overridden if needed by the subtype
                if ($g = data_get_field($fieldType, $data)) {
                        // trash out everything
                        $g->delete_content_files($field->recordid);
                }
                //delete the content itself
                delete_records('data_content','id', $field->id);
            }
            print get_string('deleted', 'moodle') . ". " . get_string('entry', 'data') . " (ID".$record->id.")<br />\n";
            flush();
        }
    }

    // delete all the records
    delete_records('data_records', 'dataid', $id);
    // delete all the fields definitions
    delete_records('data_fields','dataid',$id);

    // Delete the instance itself
    $result = delete_records('data', 'id', $id);
    // delete the grades for this db
    data_grade_item_delete($data);


    return $result;
}