DSL for pretty standard object model with a mapping to an SQL DB

I need a DSL (for Xtext) for describing a pretty standard object model:

• There are entities
• They have fields which can either be primitives or references to other entities
• References can be 1:1, 1:N, N:1 or N:M

Not 开发者_StackOverflow中文版wanting to reinvent the wheel, what DSLs exist that implements this?

I believe that the current version of Xtext embeds an example that looks just like what you need.