Hi

and thanks for reading all that stuff :).

The problem in principle here is very similar to
http://groups.google.com/group/h2-database/t/5a3a1eccac322abc, so I
can cut most of the blabla this time.
It simply is about architecture: SCRIPT just dumps a structure-
reproduction DDL script. But what is required for proper architecture
is for the application to "understand" the DBMS's structures (= read
the meta data and build the structure abstractly from it to have
something to work on). Oh btw. still SCRIPT is a cool function, no
doubt :D.

To your question:
It's for potentially all DBMS (and an earlier version of my lib is
already in production use with adaptors for multiple DBMS), but H2 is
the first to be used with the extended features of handling
constraints etc.
Still I can already tell from experience: Some of them will provide
all the required data, some won't. As usual. For the bulky ancient
DBMS, I don't even bother to talk to their support about such things
but just say "not possible, blame the ancient DBMS". H2 in contrast is
modern and cleanly written enough to actually fix stuff like that, so
I try it :).

Also H2 shouldn't hide behind the deficiencies of ancient DBMSs. As
far as I understand it, H2 is meant to provide a better alternative,
not just say "well it doesn't work but the others don't, either".


The feature missing in H2 is:
As one INDEX can be used by n FOREIGN KEYS, it's not sufficient to
provide the name of one FK that uses the index, but of ALL FKs using
the index.
The easiest and cleanest way to do so is to extend the
I_S.CROSS_REFERENCES table with a column FKTABLE_INDEX_NAME (or so)
that provides the information "this FK uses that INDEX".
Similar to the already existing column PK_NAME.

As far as I could see into H2's internal structures and the working
workaround procedure, this should be very easily implemented.
Again of course only with low priority, fully understandable.


Regards



On Dec 16, 11:05 am, Thomas Mueller <[email protected]>
wrote:
> Hi,
>
> > I am trying to automatically and generically read the structure of a
> > DB from the INFORMATION_SCHEMA to build up a data structure
> > representing the DB.
>
> Is this just for H2 or for other databases as well?
>
> Do other databases provide all the data you need? If yes, what feature
> is missing in H2?
>
> If it's just for H2, I suggest to use the SCRIPT statement.
>
> Regards,
> Thomas

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