This topic set contains a collection of the most-common db4o usage pitfalls.
Equality Comparison
Reference Cache In Client-Server Mode
Storing BigDecimal
Storing MarshalByRef Objects
Storing Timestamp And Date Values
Transparent Activation
Transparent Persistence
Accessing Persistent Classes From Different .NET Applications
Activation Depth
Classloader And Generic Classes
Client-Server Timeouts
Dangerous Practices
Update Depth
Working With Large Amounts Of Data