Hi everybody,
I would like your opinion regarding the use of ORM in web applications
built with GWT. I'm a little reconsider about the ORM, and I wonder
whether it is worth to use in web applications built with GWT. What
would be real advantages in addition to greater independence and
portability?
Waiting for your comments
For me this is a surprisingly difficult recommendation to make. For most
of the decade I've been using primarily ORMs - either Hibernate or
Toplink with native APIs, or for the past 3-4 years Hibernate or Toplink
Essentials/EclipseLink with JPA. Before that, in the Java/J2EE world, it
was JDBC. I've also used iBatis/MyBatis, and raw JDBC even recently.
After the past 3-4 years of using ORMs with JPA, mostly JPA 1.0 but some
JPA 2.0, on applications of moderate load (100-300 concurrent users) and
moderate complexity (200-300 entity classes), I've come to the following
conclusions:
1. For small applications it doesn't matter what you use: JDBC, a
non-JPA mapper like MyBatis, or a full-fledged ORM with JPA like
Hibernate or EclipseLink. All of them will work, with about the same
amount of effort, and none will be more problematic than any other;
2. For larger applications I can't in all good conscience recommend
full-fledged ORMs with JPA anymore unless it's:
a. in that subset (whether it's 10 percent, or 25 percent, or whatever)
of large applications that have persistent objects and usage patterns
that are well-served by JPA (*);
b. you have a team of persistence layer developers who have substantial,
hard-earned experience with all of - the target database, JDBC, the
target application server, and the specific chosen ORM. There are dozens
of ways to get bit with JPA ORMs, and sooner or later every one of them
will get you. You'll see exceptions and encounter problems that you will
never have with JDBC.
So I'm not discounting JPA ORMs completely - I simply don't think they
are an automatic first choice. Unfortunately you (or someone on your
team) needs to have significant experience with a large JPA project
before you know whether it's a reasonable choice. It's not possible -
IMHO - to make a general recommendation that favours JPA.
AHS
* this sounds like a circular objection, but it makes more sense once
you've gone through the agony of using JPA on a large project that
really doesn't benefit from it...or is actively hindered by using it.
--
That's not the recollection that I recall...All this information is
certainly in the hands of the auditor and we certainly await his report
to indicate what he deems has occurred.
-- Halifax, Nova Scotia mayor Peter Kelly, who is currently deeply in
the shit
