Matthias Kuhn be01b7eec5 [FEATURE] Add N:M relation editing possibilities ...

This adds the possibility to manage data on a normalized relational
database in N:M relations. On the relation editor in a form, the tools
to add, delete, link and unlink work (also) on the linking table if a
relation is visualized as N:M relation.

Configuration is done through the fields tab where on the relation a
second relation can be chosen (if there is a suitable relation in terms
of a second relation on the linking table).

Limitations
===========

QGIS is not a database management system.

It is based on assumptions about the underlying database system. In
particular it expects

 * A `ON DELETE CASCADE` or similar measure on the second relation
 * Does not take care of setting the primary key when adding features.
   Either users need to be instructed to set them manually or - if it's a
   database derived value - the layers need to be in transaction mode
   (currently only activatable through the API)

2015-12-08 15:49:01 +01:00

..

travis

[FEATURE] Add N:M relation editing possibilities

2015-12-08 15:49:01 +01:00