Re: [Vala] Is there any way to deserialize something into object in vala?

[Daniel Espinosa <esodan gmail com>]

I don't know about json-glib, but GDA uses a GObject/GLib C API to wrap C
API from its providers, provides prepared SQL commands to be executed
directly by the providers, and so on. Look at http://www.gnome-db.org/

Vala extensions are written in pure Vala. It just use GDA Vala bindings to
get access to the Database and run queries to save/load fields, this is at
least for GdaData.Record class. Record class is a pure Vala implementation
that use Gee classes, it internally uses Gda.SqlBuilder to run queries on
load or save data; they are run when you call update() or save() methods,
but you can dinamically set fields' value using set_field(), no access to
database are performer jet. An example for GdaData.Record is:

http://git.gnome.org/browse/libgda/tree/samples/vala/SampleDataObject.vala?id=b71b62ab68ddec29637f59dc05ae270ed10efee5

May be the only object you will get a penalty in performance (what are your
requirements? Real Time?) will be GdaData.Table class, but just for
update(), because it uses GDA's metadata updates to know fields, types,
keys, foreign keys and referenced tables, but this is just for the first
time, you will be able to use Gee classes to get access to metadata
directly. With GdaData.Table you can create tables without run "CREATE"
statements, just set the fields you need, keys, foreign keys and other
data, and run save() to actually run a query into the database. I'm writing
an example for Table class, but in the middle you can check Unit Tests at:

http://git.gnome.org/browse/libgda/tree/tests/vala/CheckTable.vala?id=b71b62ab68ddec29637f59dc05ae270ed10efee5



2012/3/22 marcin saepia net <marcin saepia net>

> Hi Daniel,
>
> thank you for your suggestion. I was considering GDA but as
> performance is quite important in my project, I wanted to recreate
> minimal subset of functionality of database abstraction layer by
> myself and do that in Vala.
>
> GDA is written in C, so it propably uses the same macros that
> json-glib does. But I still wonder if it is possible to do that in
> pure Vala?
>
> m.
>
> 2012/3/22 Daniel Espinosa <esodan gmail com>:
> > May you want to test GDA's Vala extensions.
> >
> > They provides a Record object that could be used as a base class for your
> > objects and save all your properties directly to a database. Check out
> > samples/vala code.
> >
> > Vala extensions are available from git.gnome.org/libgda
> >
> > El mar 20, 2012 7:04 a.m., "marcin saepia net" <marcin saepia net>
> escribió:
> > > Hi,
> > >
> > > I need to create a sort of abstraction layer between the database and
> > > my vala app.
> > >
> > > It would be great if it was possible to interate over my class
> > > properties, read they type etc. and dynamically map fields from the DB
> > > to the properties.
> > >
> > > Is there any way to do that?
> > >
> > > I know that it is possible within GObject, as json-glib has that
> > > functionality, but is it possible without access to low-level C
> > > GLib/GObject macros? Only in Vala?
> > >
> > > m.
> > > _______________________________________________
> > > vala-list mailing list
> > > vala-list gnome org
> > > http://mail.gnome.org/mailman/listinfo/vala-list



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