Db4o Note: Db4o.configure() != Db4o.newConfiguration()

In earlier versions of Db4o we used Db4o.configure() to configure all Db4o database globally (across all ObjectContainer). However in 7.2 (and above) versions of Db4o Db4o.configure() has been deprecated and it is suggested to use Db4o.newConfiguration() instead. Unfortuanately they do not clearly mention anywhere that these two functions are not equivalent. I assumed they are equivalent like Db4o.set()is equivalent Db4o.store() or Db4o.get() is equivalent to Db4o.queryByExample().

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Biggest Db4o Gotcha!

Db4o is an excellent open source object database for Java & .NET platform by Carl Rosenberger's team. I highly recommend it for rapid prototyping and RAD. It transparently handles object storage and retrieval. Today I will talk about the single biggest gotcha in Db4o which is bound to stumble any newcomer as well as pros who haven't been using it in a while.

In Db4o you can create an complex objects with other objects as its member and Db4o will save them all like a champ with a single set() (now store()) method. So intuitively you try to use the same concept for updating the database. This is where you will stumble. Db4o by default doesn't recurse when updating an object.The stranger aspect is that when you save it to the database with a store or set and then retrieve it again it will appear to work fine. However after you close and re-open the database your data will be lost! This is the single most baffling feature I found in Db4o.

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