If it is just about creating and managing the database and you can use SQLite, then take a look at this page:
List of Management Tools for SQLite
There are a lot of tools listet, that work with SQLite and there should certainly be one that suits your need.
Also, I think you are using the wrong term with ORM. What you want is a management tool, where you can build your DB with a designer. An ORM system is basically a mapper between your database and your programming language. ORM would come in to play, when you want to represent your database in code.
See the description from wikipedia:
Object-relational mapping (ORM, O/RM, and O/R mapping) in computer software is a programming technique for converting data between incompatible type systems in object-oriented programming languages. This creates, in effect, a "virtual object database" that can be used from within the programming language. There are both free and commercial packages available that perform object-relational mapping, although some programmers opt to create their own ORM tools.
Wikipedia page on ORM