Signed-off-by: Aurélien Dunand <aurelien.dunand@tdf.fr>

This tag won't work on previous job as we miss information about the job
instance used in the job pickled data file. So instead return unkown for
those old jobs.

This tag report the numeric id of the job, the id part after the 'job-'
string.

Signed-off-by: Antoine Millet <antoine.millet@arkena.com>

Signed-off-by: Antoine Millet <antoine.millet@arkena.com>

Signed-off-by: Antoine Millet <antoine.millet@arkena.com>

As it is not used and broken (type_ is not kept).

With the permission of Romain Degez, CTO of Smartjog.

Signed-off-by: Sébastien Luttringer <sebastien.luttringer@smartjog.com>

Signed-off-by: Antoine Millet <antoine.millet@smartjog.com>

Allows these methods to be overidden in subclasses.

This change should fix the "dictionary changed size during iteration" caused by
a database modification while query processing initialization.