Re: [gnome-db] constraints

["Vivien Malerba" <vmalerba gmail com>]

On 10/19/06, Stian Skjelstad <stian nixia no> wrote:
> > > Implementation missing: database_constraints_update_list() in
> > > gda-dict-database.c line 1167
> >
> > Yes, some features are still missing... The current implementation
> > uses PK and FK fields as reported by the TABLES schema query to
> > maintain the list of constraints; it works but there are some
> > limitations which will be removed when we use the CONSTRAINTS schema
> > query.
> >
>
> I assume this is a something that will be done before the 2.x
> release :-p

No, it's for after the 2.0 (for the 2.2 probably) as it is currently
working wuite well and I don't want to introduce big code changes now.

> > >
> > > And no forreign keys is visable. I want to fix the mysql provider to
> > > support mysql 4.x foreign keys, but in order to implement it, I need to
> > > trigger the function that reads them, and it never got hit. Just got the
> > > message above.
> > >
> >
> > Two solutions to make it work now:
> > 1- make sure the TABLES schema query correctly reports PK and FK
> > fields for MySQL 4.x
> > 2- make sure the CONSTRAINTS schema query reprts them for MySQL 4.x
> > and modify libgda to use that schema query instead of the TABLES
> > schema query to maintain the list of constraints.
>
> Both methods would use the same code, since they will need to parse the
> output from SHOW CREATE TABLE.

Yes, in the MySQL provider that could be the same function if it makes sense.

> Another question when we first are at the question about missing
> features. mysql table query, should also put out the engine used. Why?
> If you want to create FK, the table you refer to has to be innodb (or
> other engines that supports FK). The point is, the user needs to be able
> to lookup the engine used, without haveing to do manual queries.

Yes, I agree. The GDA_CONNECTION_SCHEMA_FIELDS schema query has a last
attribute named "extra" which now currently can only contain
"AUTO_INCREMENT" if the corresponding field is auto incremented. That
column is a list of comma separated extra attributes, and we could add
an attribute like "MYSQL_ENGINE=INNODB" (or other MySQL engines of
course). If you implement this in the MySQL provider, then I can
update the documentation.

> > I suggest you do the first point first (as it's easier and you'll get
> > an immediate result), and then if you want do the 2nd.
>
> I would be happy to look into it. It might take some time, since I'm new
> to this project, and that my time is limited.

No problem as it can be for after the 2.0!

Regards,

Vivien