Hi all, I have some questions regarding table joins in QGIS.
Looking at the GUI, there are two locations where such "joins" can currently be declared : - through the "Joins" tab of a layer's properties (1:1 join) - through the "Relations" properties of the project (1:N joins) Relations are very cool when used in edit mode on a layer (see http://blog.vitu.ch/10112013-1201/qgis-relations). But nothing appears in the attribute table, there is no new columns (which is the case for a "Join" definition), so I guess one cannot use "related" fields for symbology, labelling, and so on (even with some assumptions on the relationship, like that is really a 1:1 relationship) This seems a bit confusing to me, because they seem very closely related concepts (and well-known concepts in databases), I find strange to have them defined at two locations. I did not yet have a look at the code, but are there any chance we can treat fields of a "relation" as first-class fields in a layer ? The idea would be to use them to define 1:1 (current "joins") and get rid of layer's "joins". We are also asked for the possible addition of spatial joins within QGIS. I would find it nice to be able to define them as "relations". Probably starting with a 1:1 "intersects" join, but with an open possibility for 1:N spatial joins (contains, etc.), and why not free custom user expressions as join predicates (including "left" and "right" geometries for instance) -- Hugo Mercier Oslandia _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
