[baseten-users] updating of SQL-views

[Tuukka Norri]

Hi and sorry about taking some time with this.

Patrick De Visschere kirjoitti 30.1.2010 kello 15.37:
> I have a single table and an SQL-view of that table; baseten is connected to the view and the required SQL-RULES are present.
> - when I make changes in the table with pgAdmin, these are not shown in the Cocoa-views. This is probably normal since baseten is connected to the SQL-view. I enabled also the underlying table with the assistant but that makes no difference.
Unfortunately the change notifications have been implemented in such a way that changes in underlying tables won't currently be noticed. We did experiment with cascading notifications but they turned out to be more problematic than what they were worth.

> - let's say that 1 column of the table is the sum of 2 other columns (the sum is calculated by PostgreSQL) ; when I make changes in the Cocoa-views then the  SQL-table is properly updated but the sum never shows up in the Cocoa-view although it's value is returned by the RETURNING clause in the SQL- view RULES.
When updating views only the primary key values are fetched, so changing the rule won't help.

> - The view also contains a running-total; should this also be updated automatically by BaseTen in the Cocoa-views?
I would expect that it won't be updated.

I can only offer some workarounds to the problem. If the calculation is simple, you could write a custom getter with a matching +keyPathsForValuesAffecting<Key> method. You could also use key-value coding operators [1]. Another                                                                   option is to use key-value observing to get a notification when a column gets updated and call -[BXDatabaseObject faultKey:] with the name of the column that contains the calculation as the argument when that happens.

[1] http://developer.apple.com/mac/library/documentation/cocoa/Conceptual/KeyValueCoding/Concepts/ArrayOperators.html
-- 
Best regards,
Tuukka Norri
MK&C