Name.php

<?php
class ZendDbSchema_Validate_Db_Schema_Table_Mysql_Column_Name
    extends Zend_Validate_Abstract
{
    const NAME_EMPTY      = 'columnNameEmpty';
    const EXISTS          = 'columnExists';

    protected $_messageTemplates = array(
        self::NAME_EMPTY      => "Column name can not be empty",
        self::EXISTS          => "Column with name %value% alteady exists in table"
    );

    public function isValid($value)
    {
        $schema = null;
        if ($value instanceof ZendDbSchema_Db_Schema_Table_Column) {
            $schema = $value;
            $value = $schema->getName();
        }
        if (empty($value)) {
            $this->_error(self::NAME_EMPTY);
            return false;
        }
        if ($schema && $value !== $schema->getOriginName()) {
            if ($schema->getTable()->columns()->has($value)) {
                $this->_error(self::EXISTS, $value);
                return false;
            }
        }
        return true;
    }
}