Changes between Initial Version and Version 1 of S3/Context

Timestamp:

05/12/14 11:23:03 (12 years ago)

Author:

Fran Boon

Comment:

--

S3/Context

@@ +1 @@
+= Context =
+
+A context is a way of defining a filter for a resource by it's links to another resource.
+
+We access the filters via a common [wiki:S3/FieldSelectors FieldSelector] despite the back-end ther actual linkages varying from being as simple as a foreign key or going through a link table:
+ * [wiki:S3/FieldSelectors#ContextPaths]
+
+The context filters are usually defined in the core models ({{{modules/s3db/*.py}}}), like:
+{{{
+s3db.configure("project_project",
+               context = {"location": "location.location_id",
+                          "organisation": "organisation_id",
+                          },
+               )
+}}}
+
+This shows that:
+* if we want "All Projects related to Organisation X" then the back-end will do this by using the simple Foreign Key 'organisation_id', although we can access that via {{{(organisation)}}}.
+* if we want "All projects related to location Y" then the back-end will do this through the 'location' [wiki:S3/S3Model/ComponentResources Component], although we can access that via {{{(location)}}}.
+
+Contexts get used a lot by [wiki:S3Profile Profile pages].