[Springframework-developer] OT : Anyone know of a solution for storing (and retrieving) hierarchical data efficiently?

[Cameron B. <ca...@da...>]

I am implementing a system that needs to store a fair bit of hierarchical
data.

 

For previous apps that have had this requirement, I stored the hierarchy in
relational databases, which worked sufficiently well.

 

BUT, this new application has a lot of operations that deal with deep and
wide directed trees (I don't know if that is the correct name for them, but
I am sure you get the picture).

 

This would require a LOT of trips to the database to fetch the children each
time a transaction runs.

 

I could try and implement this using some complex caches but I though I
would see if anyone else has an alternate solution.

 

It will need to be able to participate in a distributed transaction, since
some data will be stored in a relational database, and some in the hierarchy
store.

 

I have thought of products like

 

*	Prevayler http://www.prevayler.org <http://www.prevayler.org/> 

*	seems a little amateur from the wiki
*	seems to support transactions
*	needs to keep all data in memory - which probably won't work for
this site
*	doesn't seem to support JTA

*	Berkeley DB Java Edition -
http://www.sleepycat.com/products/je.shtml 

*	Supports transactions
*	doesn't seem to support JTA
*	may be too low level

*	JDBM http://jdbm.sourceforge.net/

*	Simple transactional persistent hash map implementation

 

Does anyone have any suggestions on other 'preferably' open source products,
or techniques to achieve wish to do.

 

I am also very new to XA and distributed transactions, so if anyone has any
hints on using XA with spring please show me where I can find some
resources.

 

Also - it is possible to implement XA support for systems like jdbm,
prevayler or Berkley db ?

 

Cameron.