Re: ORM or JDBC?

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 24 Mar 2011 22:16:10 -0400

Message-ID:

<4d8bfae8$0$23757$14726298@news.sunsite.dk>

On 24-03-2011 09:16, Michal Kleczek wrote:

But JDBC is a pretty damn good generic DAL by itself

JDBC is not a DAL.

It allows you to write thousands of lines of code that is
a DAL.

ORM makes sense when there _exists_ an object model that _implements_
business logic (so JPA entities would not be _used_ by a "business logic
layer" but rather _are_ business logic if you can say it that way).
And by "business logic" I mean logic that is _specific_ to the purpose of
the application. So if the application is about presenting/manipulating data
using GUI - it would be a GUI library of choice.
The problem with existing ORM tools (and JPA is no different) is that they
are not capable of mapping arbitrary object models to arbitrary data models
for example:
map a general ledger database to a Swing GUI object model

No.

Because that would be a horrible design.

map a billing database to an object model defined by a neural networks or
linear programming library

No.

Because that is not a DAL.

Arne