I'm not here to debate whether identities or sequences are good or
bad.  Just to inquire about how you might approach a situation where,
for various reasons, you need to have different physical dbms models
beneath your mappings. This is just one example.

Fact is, I'm not in a position to change the whole way my existing SQL
server application does business at this point. I would like to keep
my mapping layer generic, if possible, as I extend it to support other
db types.

It seems to me that, for the same reasons that the database-object
element has dialect-scope, maybe all mapping elements could benefit by
supporting a similar mechanism.  It'd make the XSD more challenging
maybe, but to me at least, well worth it.




On Sep 28, 7:06 pm, Jason Meckley <[email protected]> wrote:
> use guid, guid.comb or hilo. Not to mention sql identity breaks the
> entire UOW concept with NH. You also loose the ability to batch
> commands.
>
> On Sep 28, 6:01 pm, rsr <[email protected]> wrote:
>
> > Wondering how to approach the following
>
> > Suppose I want to support both SQL and Oracle, using the same domain
> > model, and mapping files.
> > Mostly, this works out nicely, and the mapping files are generally
> > "dialect neutral".
> > But I can see one problem so far, where it isn't quite so, the case of
> > id generator types.
>
> > Consider the following hbm snippet
>
> >     <id name="Col1" type="int" unsaved-value="0">
> >       <column name="Col1"/>
> >       <generator class="native">
> >         <param name="sequence">axiom_seq_2</param>
> >       </generator>
> >     </id>
>
> > Here, i have used the native generator class, which gives me
> > identities with SQL and sequences with Oracle. I can further control
> > the sequence using params, which are only used with Oracle.
>
> > That kind of works, but there are a couple of problems and, what I
> > really want is to be able to use a generator element with
> > class="identity" for SQL and with class="seqhilo" and parameters for
> > Oracle.
>
> > Like, if each mapping element had a "dialect" attribute or something
> > that would cause the element to be ignored if the current dialect
> > doesn't match.  Any thought given to that sort of thing ever?
>
> > Is there some other mapping approach that would let me do this?  I'm
> > considering adding my own attribute to the XML and then filtering on
> > it when I add the resource file. Not ideal, but I don't see a better
> > way.
>
> > Suggestions?
>
>

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