2008/11/20 Murray Cumming <[EMAIL PROTECTED]>

> On Thu, 2008-11-20 at 20:30 +0100, Vivien Malerba wrote:
>
> >         I still don't understand. Is the "this field is a primary key"
> >         information something that is stored in the server (PostgreSQL
> >         in this
> >         case) or not?
> >
> > The default is, as for V3, that Libgda creates its own dictionary file
> > (in V3 it was an XML file, and in V4 it's an SQLite DB file). This can
> > be changed and it's possible to store the meta data in the database
> > being accessed. See
> >
> http://library.gnome.org/devel/libgda/unstable/gda-dict.html#GdaMetaStoreSetupfor
>  some example.
>
> Is it normally in the database server, other than in this extra libgda
> meta data that you store in the database?


It's up to you (as a programmer) to decide how you organize where data is
stored. For example the foolowing stiuations:
* the gda-sql console tool for example can't afford to modify the database
schema which is accessed for its own needs (no generic tool can), so it uses
a separate SQLite database file (located in ~/.libgda) to store the
extracted meta data and some of its own data
* if the database being accessed is managed by you (eg. you define its
schema), then you can decide that the meta data will also be stored in that
database (so you end up with only one database which is easier to manage).
* if you're not interrested in meta data then you don't have to worry about
the meta data DB at all.

This offers much more flexibility than there was in V3.

I guess you use a special table to store that metadata. Is that table
> name and data format documented somewhere?


There are several tables and views (all starting with an undersore), see the
description here:
http://library.gnome.org/devel/libgda/3.99/information_schema.html

Cheers,

Vivien
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