Hi,

We have been having some troubles in our project consistently dealing with our mappings of BigDecimal values.

We have many numbers sprinkled throughout our domain model that represent distinct basic number types:
- Money
- Area
- Volume
- Percentage

Each of these numbers has a defined scale that we want to be applied consistently (2 for the cents in a dollar, 4 for the meters in a hectare, etc.)

I figured encapsulating these types in a custom domain value class and associated hibernate UserType would be a good way to do this.

The only problem is, I can't figure out how to affect the schema generation phase for a particular UserType.

Basically, each UserType just wraps around a BigDecimal and I'd like the Hibernate Schema Exporter to create the associated database column with the correct scale in the database.
At the moment, the schema exported seems to just default to precision=19, and scale=2 (Not sure if that's a database default or what).

Is there any way to control the column definition that Hibernate will issue for a custom type?

I've looked in the reference manual and the 2nd edition book, not much there that I can see.

Thanks,
Shorn.

Ok,

I found a way to do this, but it seems like a bit of a hack to me - I think Hibernate probably supports a more elegant mechanism, I just can't figure out what it is.

Basically, I make my custom user type return a non-standard, made-up value from it's "public int[] sqlTypes()" method.

Then in my custom Dialect subclass, in this constructor, I call the "registerColumnType()" method passing my special SQL code and the database column declaration I want used ("decimal 12, 2", for example);

This seems pretty dodgy, I'm binding my Dialect to my custom UserTypes pretty heavily.

It seems like Hibernate pretty much supports this kind of behaviour, I just seem to be missing the part where you hook up the custom user type to the dialect in a more robust way.

Is there something I've missed - or this pretty much the accepted way to do it?