store list in key value database

Question

I search for best way to store lists associated with key in key value database (like berkleydb or leveldb)

For example: I have users and orders

Answer 1

In BerkeleyDB you can store multiple values per key, either in sorted or unsorted order. This would be the most natural solution. LevelDB has no such feature. You should look into LMDB(http://symas.com/mdb/) though, it also supports sorted multi-value keys, and is smaller, faster, and more reliable than either of the others.