In terms of raw mapping capabilities ("what can be mapped, and how"),
hibernate basically has cayenne beat at this point.
For example, hibernate supports things lie mapping to-many
relationships as lists, arrays, or maps ( cayenne currently only
supports mapping them as lists).
Cayenne may have some mapping facilities not in hibernate, but none
that I'm aware of offhand (maybe the extended types facility? Not
sure if hibernate has an equivalent to that,
but they probably do; oh, when I first starting using cayenne,
cayenne supported "lazy" relationship fetching and hibernate did not,
but hibernate now supports it).
As you mentioned, cayenne has the modeler, whereas hibernate does not
offer any such support (except through 3rd parties). ANd that, in my
mind, is the biggest difference. Not the modeler,
but the mindset. Hibernate is about "let's make an ORM with lots of
features". Cayenne is about "let's make a tool and library that
makes developers productive".
When I first delved into the world of ORM, I spent three days trying
to grok hibernate. Finally, recalling that some other users of
tapestry were using cayenne, I tried it.
Two hours later, my objects were mapped and created, my schema was
created, and I was writing my objects. I've never looked back. I
wish I could say that dichotomy has lessened;
that the hibernate people had realized "hey, people might actually
want to /use/ our project, instead of admire our technical genius
from a distance", but it doesn't appear that that's the case.
On their website, they have a "roadmap to getting started quickly
with hibernate". Here's their roadmap:
"Day 1: Work with the tutorials
* Download Hibernate 3.2 and extract the archive.
* Reference documentation: Read the tutorial, work with the
source code in the /doc/tutorial/ directory of the Hibernate package.
This tutorial covers a simple Hibernate standalone and web application.
* Java Persistence with Hibernate: Read the tutorial in the free
sample chapter 2 of the book, download the Hello World code. This
tutorial is a complete introduction to Hibernate, Java Persistence,
and EJB 3.0.
Day 2: Read the Documentation
* Read the rest of the reference documentation.
* Consider reading the rest of the book Java Persistence with
Hibernate.
* Read the FAQ.
Day 3: Start Coding!
* Many examples you find on the Net are still Hibernate 1.x or
2.x - read the migration guide for a list of differences to Hibernate3.
* Many good patterns can be found on the Wiki Community Area,
such as Sessions and transactions, Open Session in View, Generic Data
Access Objects, ...
* Once you are familiar with basic Hibernate, download the
CaveatEmptor example application."
(from: http://www.hibernate.org/152.html)
That's their "getting started quickly"... any questions? ;)
(I could also point out things like: why is the web page named
152.html? Is that: 152 hours of frustration before starting
hibernate? Is that 152 days of reading before you start? 152 things
you have to do before you understand hibernate? Granted, the name of
a web page has nothing to do with the technical quality of the
hibernate code. The technical quality of the hibernate code is, I'm
sure, very good. But it harks back to my original point of the
paradigm of the two projects. 152.html is not a name that you could
guess as a user. Similarly, the hibernate "way" is nothing something
you can guess your way through and be pleasantly rewarded when
something that you tried thinking "I wonder if this will work"
actually does.
Now compare that to cayenne's quick start for cayenne version 2.0.
http://cayenne.apache.org/doc20/quick-start.html
Hey, look, I know what that url is telling me... and I generally know
what the cayenne API is telling me and asking me, even before reading
the javadocs...
without reading other tutorials...
For me, that's one of the key differences, and one of the main things
that keeps in using cayenne. Keep in mind, this is all user
perspective. I'm sure there are people out there who find hibernate
easy to use... erm, maybe?
Robert
PS: cayenne also has ROP, which hibernate doesn't, so if you
interested in writing swing front ends (truly "rich" client apps,
instead of lame webapps... oops, did I say that? ;), cayenne is a no-
brainer...
PPS:
On Aug 9, 2007, at 8/91:23 PM , Joe Baldwin wrote:
This is a general question I would guess at the "use case" level.
I was recently in a conversation in which I was challenged about
the selection of Cayenne over Hibernate. I have only researched
Hibernate & run some elementary demo tests. My conclusion was that
Hibernate allows you to create a mapping via an XML metadata file
but that some of the mapping responsibilities (currently found in
Cayenne) are left to the programmer to resolve and maintain. I
specifically pointed to Cayenne Modeler as an example of an
essential tool supporting the 'change it in one place' philosophy
that impacts maintenance time budgeting.
It was asserted that Hibernate could do anything that Cayenne could
do. In addition, the CayenneModeler advantage was dismissed with a
comment concerning an Eclipse plugin that is supposed to support
the same features.
Things change very quickly in the OpenSource world so perhaps I
could have made a mistake, however, I don't think that I am that
far off the mark. Is there a white paper that might discuss the
differences (couldn't find one at the Hibernate site)? Does anyone
have an opinion?
