Build relationships

[Ojaybee]

New versions of QGIS allow relationships to be viewed direct in the browser. Not sure how these work with selections etc. Building relationships for earlier versions can be done so using the qgs project but for later versions they can be built into the DB and natively read by QGIS.

[cesarcorreo]

Thanks for the plugin.
I find it very interesting that an option in the plugin allows you to maintain (or create) relationships based on the loca_id field.
I'm actually using the Model Builder to automate the regeneration of location relationships with each of the tables, and I'm also taking the opportunity to add some filters to the results.

[Didymograptus]

There are some limitations set on the relationships for GeoPackage in the QGIS Browser interface. This evidently is due to the configuration of the cardinality of relations in GeoPackage itself. https://docs.ogc.org/per/17-093r1.html#_cardinality.
Essentially, only many-to-many relations can be set in the database using the relationship extension. QGIS uses this to create two relationships (forward and Backward), which make life very confusing.
I need to explore relationships set by foreign keys in the DB to see how that works in QGS.
At the moment I create relationships using the Relationship Manager plugin https://github.com/fgianoli/RelationshipManager/tree/main, which is buggy, but works if you create a json file and upload it.
{ "LOCA-ISPT": { "nome": "LOCA-ISPT", "referencing_layer": "ISPT", "referenced_layer": "LOCA", "chiavi": { "LOCA_ID": "LOCA_ID" } } }