Name.php

<?php
class ZendDbSchema_Validate_Db_Schema_Table_Mysql_Index_Name
    extends Zend_Validate_Abstract
{
    const NAME_EMPTY      = 'indexNameEmpty';
    const RENAME          = 'indexRename';

    protected $_messageTemplates = array(
        self::NAME_EMPTY      => "Index name can not be empty",
        self::RENAME          => "Cannot change name of existing index"
    );

    public function isValid($value)
    {
        $schema = null;
        if ($value instanceof ZendDbSchema_Db_Schema_Table_Index) {
            $schema = $value;
            $value = $schema->getName();
        }
        if (empty($value)) {
            $this->_error(self::NAME_EMPTY);
            return false;
        }
        if ($schema && $schema->isDirty('name')) {
            if ($schema->isExist()) {
                $this->_error(self::RENAME, $value);
                return false;
            }
        }
        return true;
    }
}