Hi folks,

I'm a nooby with Hibernate so bear with me... We have a model classes, beans if you like, that have the hibernate xdoclet tags to generate the xml mapping file. And we are planning to re-use these models for multiple projects. But recently a client requested that SQL Server was to be used instead of Oracle. So without keeping two versions of the model files is there a way to have the Id Generators work for both database types??

I know that sequence is Oracle and identity is MSSQL. I also saw native that hibernate would take care of which ID Gen to use, but how does that work? With sequence, you have to pass in a parameter for the sequece name, how can I do that with native? Or is there another way?

Thanks a bunch in advance

Jay

In oracle Hibernate will use as default a sequence named HIBERNATE_SEQUENCE, but I dont know if you can use the sequence parameter

But how will that work if I have more than one sequece? I cant have one sequence generate IDs for 20 tables, it will be kinda wierd and a total mess.

Why would that be a total mess, these are surrogate keys without any business meaning.

I think my clients will frown upon having tables with

Table A
aID b c
1 a 23
5 x 67

Table B
bID d c
2 f 85
4 y 34

Table C
cID d e
3 h 9
6 o 4


Would anyone want this type of data? I'm sorry but thats just not clean to me.

-Jay

hmmmm.... check this out!!

Can I use the generator class 'native' and still leave the param tag for the sequence name..?

-Jay

I have done this with Oracle, and it worked.

An other approach would be to prepocess the mapping files and patch the id tag before feeding them to Hibernate.

HTH
Ernst

Try this: http://www.hibernate.org/170.html...

We had exactly the same requirements as yours and build this ID generator. It works like a charm and should provide exactly what you are asking for ;)

I tried this but it didnt work. It tried to use the sequence in MS SQL, and ofcourse if spit out a big exception.

I dont understand this logic!!!

*** This block will never execute ***
// -- max_lo -> max_lo
if( ! SequenceHiLoGenerator.MAX_LO.equals(TableHiLoGenerator.MAX_LO) )
{
String value = params.getProperty(SequenceHiLoGenerator.MAX_LO);
if( value != null ) params.setProperty(TableHiLoGenerator.MAX_LO, value);
}

*** This block will always execute ***
// -- sequence name -> table name
if( ! SequenceHiLoGenerator.SEQUENCE.equals(TableHiLoGenerator.TABLE) )
{
String value = params.getProperty(SequenceHiLoGenerator.SEQUENCE);
if( value != null ) params.setProperty(TableHiLoGenerator.TABLE, value);
}

thanks,


-Jay

post your exception then...



And why wouldn't be executed ?
I can tell you this piece of code works perfectly with SQLServer and Oracle since Hibernate 2.x

Maybe you haven't configure it correctly (in the ID part of your class mapping - see example at the bottom of the wiki page).

The sequence is not the table name!! What do I change to handle that?

-Jay

... the sequence is not the table name...
What does this means ?

Does it mean the name of your sequence is not the same as the name of the table where the sequence values will be used ?

Then, as in the wiki page:


Where the 'sequence' attribute refers to:
- if sequences are supported, it refers to the sequence name
- if not (fallback to hilo), it refers to the table holding the hi values

If the sequence name cannot be the same as the hilo tablename, then... write another generator yourself.

BTW: try to use "could you please" or "thank you" sometimes in your replies... It may help to get an answer.

ROFL... sorry I forget my manners when im working like crazy... and thanks for the response....

I figured it out... yeah!!! :D

Thanks for the Gen, probably will come in handy in the future...


-Jay