Re: opening multiple databases from same program

If you want to migrate data from one database to another then it is better to use the specific tool for that, for example scriptella or even db-unit.

In oracle for example, we can have dblink and symbols so we can achieve the same goal. Brief there are so many choices !

Just a small suggestion.

Rgds
Vu



--- En date de : Ven 9.7.10, Abel Birya <[email protected]> a écrit :

De: Abel Birya <[email protected]>
Objet: Re: [SimpleORM] opening multiple databases from same program
À: [email protected]
Date: Vendredi 9 juillet 2010, 19h20







 



  


    
      
      
      Hi,

I had the same issue when I started using SimpleORM since I was doing a lot of data migration scripts from one database to another. This is the strategy that I used to achieve my goals;

For example if I have an entity _User and I need to transfer it to another db. I would name the corresponding entity User. I would then follow the below procedure to achieve a seamless transfer process.


SSessionJdbc ses = SSessionJdbc. open(connection1 , "db1");
ses.begin;
// create a method to retrieve users eg
List<_User> users = _User.getUsers( ses);
// detach the records into a dataset

SDataSet ds = ses.commitAndDetach DataSet() ;
ses.close();

//retrieve the records from the dataset
users = ds.findAllRecords( _User.USER) ; // assuming that USER is the SRecordMeta variable

//open the new connection

ses = SSessionJdbc. open(connection2 , "db2");

for(_User _user: users) {
    ses.begin();
    //create the user on the other db and fill in the other variables such as name etc
    User user = ses.createWithGener atedKey() ;

    ses.commit() ;
}

ses.close();

Hope this helps.

Kind regards.
Abel

In the even

On Fri, Jul 9, 2010 at 7:02 PM, Franck Routier <franck.routier@ axege.com> wrote:
















 



  


    
      
      
      Hi,



well, AFAIK, you can't do that... !



SSessionJdbc has built-in checks that a connection is single threaded

using a ThreadLocal object. [I think Hibernate has some kind of best

practice to achieve the same goal (I'm not formal here, I didn't use

hibernate for years)]



There is only one dataSource per SSessionJdbc and one SSessionJdbc per

thread.



You could implement a different strategy to handle this part. Some work

was done along this path in a previous version of Simpleorm, for using a

single JTA transaction per session. But it is not maintained.

See simpleorm/extras/ SConnectionEJB. java



My question would be : what are you trying to achieve ?



Franck



Le vendredi 09 juillet 2010 à 17:11 +0200, Noel Grandin a écrit :

>   

> Hi

> 

> I'm opening multiple different databases from the same thread, which

> is triggering this check:

> 

>  simpleorm.utils. SException$ Error: Thread's SSession already open [SS

> 1.SkyMon]

> [0@17:08:40. 976] !SE>:     at

> simpleorm.sessionjd bc.SSessionJdbc. innerOpen( SSessionJdbc. java:129)

> [0@17:08:40. 976] !SE>:     at

> simpleorm.sessionjd bc.SSessionJdbc. open(SSessionJdb c.java:88)

> [0@17:08:40. 976] !SE>:     at

> simpleorm.sessionjd bc.SSessionJdbc. open(SSessionJdb c.java:108)

> 

> 

> What do I do?

> 

> Thanks, Noel Grandin

> 

> 

> 

> 

> 

> 

> 

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