public function dropUnique($keyConstraint = '')
    {
        // ALTER TABLE Persons DROP CONSTRAINT uc_PersonID
        // MYSQL QUERY
        $this->schema = static::ALTER_TABLE.' `'.$this->tableName.'`
            DROP INDEX
            UC_'.strtoupper($this->tableName).'_'.strtoupper($keyConstraint).'_ID';

        return $this;
    }