BMP or CMP ?

Google

Mailing List

Home

Forum Home

JBoss - Java Application Server

Struts - A MVC web framework

Tomcat - JSP/Servlet container

iText - An open source PDF Java Library

JDOM - JDOM XML Parser

J2EE - A mailing list for Java(tm) 2 Platform, Enterprise Edition

J2EE Pattern - An interest list for Sun Java Center J2EE Pattern Catalog

Servlet - A mailing list for discussion about Sun Microsystem's Java Servlet API Technology

JSP - A mailing list about Java Server Pages specification and reference

Struts & Hibernate

Subjects

•	JSP editor plugin for eclipse ?
•	org apache jasper JasperException: Unable to compile class for JSP
•	Tomcat: Connection reset by peer: socket write error
•	Cannot retrieve definition for form bean null
•	Struts Tiles Tutorial (free Struts training)
•	Where do I download Tomcat 4 0 6?
•	Data Access Object (DAO) pattern, example DAO 's
•	Where to download Tomcat v 4 1 24 from?
•	Tomcat 5 0 16 Requested resource not available
•	Oracle Connection Pooling in 3 2 2
•	Servlet : Session invalidate
•	Servlet action is currently unavailable
•	Tomcat/Struts Unicode Encoding/Decoding problems
•	Tomcat and webapplication specific java library path
•	Running a Simple JMS Example
•	Mapping in workers2 properties
•	org apache jasper JasperException
•	Cannot find message resources under key org apache struts action MESSAGE
•	problem with html:text bean throwing exception
•	Cannot find message resources under key org apache struts action MESSAGE
•	invalid direct reference problem with solution
•	Tool for jsp debug Try Sysdeo Eclipse Plugin
•	Tomcat 5 Cannot load JDBC driver class 'null ' SQL state: null
•	weblogic ejbc
•	java properties file
•	Jboss 3 2 3 Coyote Can 't re
•	Tomcat 5, Apache2 and mod jk2 integration problem
•	JBoss example problem new to J2EE
•	url string for connecting jboss to oracle
•	Value attribute of <html:checkbox
•	javax servlet ServletException: BeanUtils populate
•	HTTP Status 404 The requested resource is not available
•	5 0 18: Windows XP Pro vs Windows 2000

BMP or CMP ?

BMP or CMP ?

2003-08-12 - By Rajeev Chitamoor

Back
Are there any guiding principles/rules of thumb to determine which
persistence strategy

to use for Entity Beans. So far, we (my team) have relied extensively
upon

BMP to persist our Entity Beans, but are very interested to adopt the
CMP persistence strategy

considering some of the nice benefits it offers. The cool thing I find
about CMP/R is that it provides a

facility to 'declaratively' specify Entity relationship mapping.

Our only concern is, are there any potential pitfalls when it comes

to persisting certain kinds of object models using CMP, or in other
words,

'Can CMP be used to persist any kind of object model ?'. I know in
theory it is

possible to do so, but I was curious to hear from folks who have
successfully

used CMP as their persistence mechanism.

We have a whole bunch of relatively complex Object models (objects
graphs that are

multiple levels deep), which are currently being persisted using BMP. I
must say

that it has so far worked well.

I did come across these broad guidelines in the Core J2EE patterns book.

- Avoid inter entity bean relationships as much as possible.

- Use coarse grained objects if possible

- Composite pattern.

I sort of felt that most of the suggestions/examples (related to Object
persistence) mentioned in

the book seemed more applicable to BMP than CMP.

The single biggest concern I have about CMP is, 'Can I efficiently map

complex composite objects to a underlying relational data store ?' .

I did do some initial reading on web and also glanced through some books

(I thought Ed Roman's book had some nice examples on CMP), but most of
these examples

were not terribly complex, and I haven't come across any examples that
can alleviate my

concerns about CMP.

We are currently looking at ways to simply the current object models we
have in the

hope that it would simply the persistence mechanism.

We derive a whole bunch of intermediate data structures (for efficiency
reasons) from our

relational data to be stored in our object models which we are looking
to eliminate

as much as possible.

Any thoughts/ideas/suggestions in this area would be appreciated. Also,
if you are

currently using CMP as your persistence strategy, it would benefit my
team

hugely to know of potential pitfalls and also of any
design/implementation/testing

tips.

Thanks much

- Rajeev

====================================================================
Community Web Site (Core J2EE Patterns Catalog - Online Version):
http://java.sun.com/blueprints/corej2eepatterns
Getting Started (Beta Version):
http://developer.java.sun.com/developer/technicalArticles/J2EE/patterns/
Get the book:
http://www.amazon.com/exec/obidos/ASIN/0130648841/corej2eepatte-20 (See http://tte-20.ora-code.com)
List Archive:
http://archives.java.sun.com/archives/j2eepatterns-interest.html
Unsubscribing:
email "signoff J2EEPATTERNS-INTEREST" to listserv@(protected)

<html>

<head>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">

<meta name=Generator content="Microsoft Word 10 (filtered)">

<style>

</style>

</head>

<body lang=EN-US link=blue vlink=purple>

<div class=Section1>

Are there any guiding principles/rules of thumb to determine
which persistence strategy

to use for Entity Beans. So far, we (my team) have relied
extensively upon

BMP to persist our Entity Beans, but are very interested to
adopt the CMP persistence strategy

considering some of the nice benefits it offers. The cool
thing I find about CMP/R is that it provides a 

facility to ‘declaratively’ specify Entity
relationship mapping.

  

Our only concern is, are there any potential pitfalls when
it comes

to persisting certain kinds of object models using CMP, or
in other words,

‘Can CMP be used to persist any kind of object model ?
’.
I know in theory it is

possible to do so, but I was curious to hear from folks who
have successfully

used CMP as their persistence mechanism.

  

We have a whole bunch of relatively complex Object models
(objects graphs that are

multiple levels deep), which are currently being persisted
using BMP. I must say

that it has so far worked well.

  

I did come across these broad guidelines in the Core J2EE
patterns book.

- Avoid inter entity bean relationships as much as possible.


- Use coarse grained objects if possible

- Composite pattern.

  

I sort of felt that most of the suggestions/examples
(related to Object persistence) mentioned in 

the book seemed more applicable to BMP than CMP.

  

The single biggest concern I have about CMP is, ‘Can I
efficiently map

complex composite objects to a underlying relational data
store ?’ .

I did do some initial reading on web and also glanced
through some books 

(I thought Ed Roman's book had some nice examples on CMP),
but most of these examples 

were not terribly complex, and I haven't come across any
examples that can alleviate my

concerns about CMP.

  

We are currently looking at ways to simply the current
object models we have in the

hope that it would simply the persistence mechanism.

We derive a whole bunch of intermediate data structures (for
efficiency reasons) from our

relational data to be stored in our object models which we
are looking to eliminate 

as much as possible.

  

Any thoughts/ideas/suggestions in this area would be
appreciated. Also, if you are 

currently using CMP as your persistence strategy, it would
benefit my team 

hugely to know of potential pitfalls and also of any
design/implementation/testing 

tips.

  

 

Thanks much

 

- Rajeev

 

 

</div>

</body>

</html>
====================================================================
Community Web Site (Core J2EE Patterns Catalog - Online Version):
http://java.sun.com/blueprints/corej2eepatterns
Getting Started (Beta Version):
http://developer.java.sun.com/developer/technicalArticles/J2EE/patterns/
Get the book:
http://www.amazon.com/exec/obidos/ASIN/0130648841/corej2eepatte-20 (See http://tte-20.ora-code.com)
List Archive:
http://archives.java.sun.com/archives/j2eepatterns-interest.html
Unsubscribing:
email "signoff J2EEPATTERNS-INTEREST" to listserv@(protected)