Subforms, triggers and ntforms

[fpuga]

I open this ticket only to share some thoughts about the following case.

A form ('water system') has an embedded table ('family water consumption') that reflects a segregated data related to the main form. The main form has a field ('total water consumption') that aggregates the data and should be automatically updated when the data in the subforms change.

Right now we have a trigger in the main table that calculates the field, each time an update happens in the mainform, and a trigger in the sub table, that forces the trigger in the main table to be executed.

The problem with this approach is that even if the change is done in the database gvSIG is not being notified about it until a reload of the data (open/end edition, or a manual or code FLyrVect.reload)

There are several solutions:

• A listener in the subform window, to reload parent layer when it's closed. Bad solution because it is not needed always.
• A manual reload in the parent layer + refreshGUI in nt, when save button is pressed in the sub form. This sounds good but it should not be in the general code, as a layer reload is a heavy operation and this is a corner case.
• I don't know if exists some mechanism that allows the database notify gvSIG that the layer should be reloaded.

The second solutions implies changes in AbstractSubForm, as does not exist a saveRecord method that can be overwritten, and the SaveAction class is private and can not be injected from outside.

For sure, it can be said, that maybe triggers are not suitable for this case, but java code and views also has some corner case that make things tricky.

[fpuga]

About the third of the options i suggest, say, that there is a listen/notify mechanism in postgresql. This question in stackoverflow provides links to the original documentation.

BTW, notice that in gvSIG alphanumeric data, and geom data is handle different. As example, if you have ON DELETE CASCADE on some tables, and the referenced row is removed the referrers geometries are not shown in the view, but the alphanumeric data is still on the gvsig table or in navtable. After a manually reload of the layer, the alphanumeric data is also removed.