Spring Roo with Multiple Databases

[petersaints]

I'm having a problem trying to figure out how to use multiple databases in the same Roo project. In this case, I need multiple entities mapped to database tables, however the tables will not be placed on the same database.

There are no relationships between tables on different databases, so all I need is a way to choose a different database for specific entities. Any idea on how to achieve this?

[mmartinez]

I need is a way to choose a different database for specific entities.

You need more than one persistence units.
When you create an entity you can choose it with the "--persistenceUnit" parameter.
See documentation about it.

Regards !

[delgad9]

Hi,

I post this solution about it a while ago...

I believe this is what you are looking for.
http://viralpatel.net/blogs/spring-r...configuration/

I hope it helps you

Best Roogards
jD

[delgad9]

Hi

Newer -and cleaner-version on same solution at http://pragmatikroo.blogspot.com/201...databases.html

Again I hope it helps you

Best Roogards
jD

[LIBO SU]

Additional quetsion :
how about some one want to work "DbOne" with MYSQL, and want "DbTwo: to work with Mongodb ?

[delgad9]

@LIBO SU

That is an interesting solution to work on...
I don't have it right now but it is totally doable with Spring Data for sure.

In the meantime I invite you to visit my showcases on Mongo and Roo at http://pragmatikroo.blogspot.com/201...ves-using.html

B. Roogards
jD

[mmartinez]

how about some one want to work "DbOne" with MYSQL, and want "DbTwo: to work with Mongodb ?

Yeah, it is possible.
You need two persistence units, one configured with MYSQL and the other one with Mongodb.
Then create an entity and choose it with the "--persistenceUnit" parameter.

[petersaints]

Thanks this mostly works. The only problem I have now is that I wish I could have a default persistenceUnit. Now I have to add an annotation to every class I have so far so that it knows which database to use. Isn't it possible to define one of them as the default and only choose a different one as needed?

EDIT:
Another problem is that on application startup the tables get created on both databases. That's undesirable. How to stop it?

EDIT2:
Well... I seem to have to define each class manually on persistence.xml. This is boring!! Can't this be automated? Or at least can't I specify that all Entity classes in a given package use a specific persistenceUnit?

Example:
<class>pt.unl.fct.p2muca.domain.security.User</class>
<class>pt.unl.fct.p2muca.domain.security.Gender</class>
<class>pt.unl.fct.p2muca.domain.security.RoleGroup </class>
<class>pt.unl.fct.p2muca.domain.security.UserRoleG roup</class>
<class>pt.unl.fct.p2muca.domain.security.UserActiv ation</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>

Having to add this manually is boring!! There is no better solution?