Re: Update with keeping configuration

Ronald,

I'll break that question into two parts: why use ORM (Object
Relational Mapping), and why use Hibernate/HSQLDB

Pixory is written in Java, which is an Object Oriented Language. The
ideal persistence mechanism for an OOL would be an Object Oriented
Database, because that would allow the plain old java "domain" objects
that are at the heart of the system to be "magically and
transparently" persisted. In other words, you would not have a lot of
programmatic overhead associated with translating between the run-time
domain objects and the mechanisms of storing and retrieving their
persistent state. However, when I started project Pixory, over 2 years
ago, I could not find any open source, java, object database that
looked ready for prime-time. Even if I had, I personally have no
experience with object databases and I would have been hesitant to
adopt an unknown for the heart of the project.

You can approximate (sort of) an object database with an ORM (Object
Relational Mapping) framework. When I started Pixory, the decision was
a no brainer:

1) I had been using ORM frameworks since 1996
2) The technology is fairly mainstream and very mature. TopLink has
been around since the early 1990s (in Smalltalk).
3) I had been using RDBMs since the early 1990s.
4) SQL databases are standardized, so I could substitute different
implementations.
5) SQL databases are well understood, and have lots of third-party
tools for browsing, etc.

So the combination of ORM/RDBMS was natural for me.

Specifically, why Hibernate? I had never used Hibernate before, but I
liked the design. The design (from the user side) was simpler, lighter
than NeXTs EOF or Cayenne. It more closely resembled TopLink, which I
liked for its simplicity. Also, I tested Hibernate extensively, and it
seemed to always do what the documentation said it should do. So even
though there were lots of open source, ORM java projects at the time,
I thought that Hibernate had the highest quality.

Why HSQLDB? It seemed to work without any problems, and it was the
only open source, java, SQL, database designed for embedding, that had
a non-GPL license ;)

regards,

joe


--- In [email protected], "rpu43" <rpu43@y...> wrote:
> 
> Thx for the answers about the persistancy stuff, makes sense.
> Next question arises:
> Why use HSQL en hibernate at all?
> 
> Ronald





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