Re: Robust way of storing JDK 5.0 enum values into database

Kari Ikonen wrote: 
Basically issue is simple: How to store enum values into database. Sounds
simple, but when going after robust solution, then problems start to
appear.

That's rather putting the code before the database. Your enum values are what database textbooks will refer to as domains. Domains can be simulated in SQL with a populated table that doesn't change.

Some approaches,
- Plenty of manual coding for each enumeration
  * not generic
- Storing enum value names
  * not robust, changes when enum names are changed


If you change the names you break source compatibility.

- Storing ordinal values
  * not robust, changes when new enum values are added


If you change the ordinals you break binary compatibility.

If you must allow these things to change, without disrupting existing data, then I think you want an extra layer of indirection. Expose the enum in the API, and introduce a new type for the database. Because the new type represents one of a fixed number of possibilities, an enum is the obvious choice. But you don't have to change you implementation until the separation is actually necessary.

Tom Hawtin
--
Unemployed English Java programmer
http://jroller.com/page/tackline/
.