Two/Dual Databases

[epicdoom]

Hello!

I've gone through many threads of how to use spring roo with two databases but none are sufficient I feel. Specifically I need one database to be reverse engineered which will be a read-only database for drop down lists. And I need a second database to store other entity fields.

Most of the things I've read are outdated or have errors in them when I try to recreate. I'm pretty new at all this spring stuff so some help would be much appreciated. Has anyone done this and can link me to a sample? Or is there any kind of support for this in roo? (from what I've read/seen there is no official support?)

Thanks guys!

I was trying to recreate this dual database example:
http://viralpatel.net/blogs/2011/01/...iguration.html

but keep getting this error:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~

INFO: Deploying configuration descriptor twodatabases.xml from /home/shelby/springsource/vfabric-tc-server-developer-2.5.0.RELEASE/spring-insight-instance/conf/Catalina/localhost
Aug 15, 2011 5:50:49 PM org.apache.catalina.startup.SetContextPropertiesRu le begin
WARNING: [SetContextPropertiesRule]{Context} Setting property 'source' to 'org.eclipse.jst.j2ee.server:twodatabases' did not find a matching property.
Aug 15, 2011 5:50:49 PM org.apache.catalina.startup.HostConfig deployDescriptor
SEVERE: Error deploying configuration descriptor twodatabases.xml

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~

[delgad9]

Somehow my article wasn't published correctly...

Add following code to the configuration provided -into web.xml-:

<filter-mapping>
     <filter-name>Spring OpenEntityManagerInViewFilter1</filter-name>
     <url-pattern>/*</url-pattern>
</filter-mapping>
 
   <filter-mapping>
    <filter-name>Spring OpenEntityManagerInViewFilter2</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
 
 
on the entities  assign the correspondent persistent unit name in the annotation as shown.
 
@PersistenceContext(unitName="persistenceUnit1")
  transient EntityManager entityManager;

Roogards
jD

[epicdoom]

It's JD! Awesome blog post man. I will try this out and get back to you if it works.

I was wondering if you know
if what I described was possible. i.e. Say I have an entity that writes field string --fieldName name into the Client Databases. And in the same
entity I have another field reference which creates(reads) a dropdown list from the Master Database which is like "Select Chip-Type" and has a list of all the chips I support.

I was wondering because you said that on the ENTITIES I need to describe the "persistent unit name". And if I'm using two databases within the same entity it would cause a problem right?

Let me know if that wording was confusing.

Thanks

[delgad9]

@epicdoom,

If you liked this blog... Wait to see the book I am working on...
It is pretty much like this post. Solution very hard to find in other places. Like master-detail, column sorting, dynamic menus, jQuery integration, performance calibration and other hot issues.
All of them customized for the Roo community.

2 points:
1) On your question: I truly believe you can do with this configuration anything you can do with one db onto two or more db concurrently.
2) For more information: check the exchanges I had with other developers -at the original article website- that succeeded with the configuration after struggling a little bit in the begging.




Thank you for your comments and B. Roogards
jD

[jbbarquero]

What publisher are you going to use for your book?, is there any preview release?

[delgad9]

@jbbarquero,

Hola,

Thank you for asking...
I don't have any yet. I've tried several book houses but unfortunately they have turned me down*.
Realizing the great need from the community on certain unsolved forum frequent questions -which basically these are the solutions that I am providing.
I asked the endorsement from a VIP on the Spring Roo team several months ago. But nada/nothing has showed up on this regard. I thought that the endorsement could get the attention of a book publisher.

I let you know when I get one.

B. and unpublizized Roogards

*R.K. Rowling story is my inspiration

[jbbarquero]

What a pitty! but don't give up, and good luck

[delgad9]

@jbbarquero,

Hey muchas gracias...

Nope, I won't give up. I know my Roo solutions are hard to find -sometimes unique- and have great value.

I'll prevail.

B. and determined Roogards
jD

[delgad9]

Hello Fellow Rooists,

I posted again in my blog that deals with the configuration for accessing 2 databases with Roo. The post is at http://pragmatikroo.blogspot.com/201...databases.html. *

For reasons out my control the first one published missed few details.

The configuration has been successfully used by multiple developers all around the world with their Roo projects.


I have plans to extended the configuration for programatically manage multiple datasources instead of using verbosed xml and to include service/repository approach.


B. Roogards
jD

* The link is ok. I correct the misspell later.