Access of 1-side aggregation on the m-side via relationship

Classic Servoy
1

Hello All

I have two tables imports and import_positions. I need to have the next id (primary key) on the m-side, i. e. on import_positions. I made an aggregation idMax with type maximum on imports. On the imports (1-side) it works as expected, i. e. it gives the max number of id. But when I access this idMax field via the normal relationship on import_positions, I do not get the idMax number of the 1-side, but the id of the 1-side (I assume). I am not sure what’s wrong here.

Best regards, Robert

2

Aggregations in Servoy are in context: if you get an aggregation on a table it will get the max on the whole table, if you retrieve that through a relation it will get the max for that relation. In your case you can access the Max of that table by retrieving it on a form that is based on that table. eg
var vmax = forms.import_positions.NAMEOFTHEAGGR

3

Hello Jan

Thanks for the solution, it works. I am still wondering, for accessing a aggregation via a relationship, this behaviour never makes sense, does it? The aggregation value on the other side of the relationship has only one value, ever. I assume the behaviour is because the relationship acts (for this case unwanted) like this?

Best regards, Robert

jaleman:
Aggregations in Servoy are in context: if you get an aggregation on a table it will get the max on the whole table, if you retrieve that through a relation it will get the max for that relation. In your case you can access the Max of that table by retrieving it on a form that is based on that table. eg
var vmax = forms.import_positions.NAMEOFTHEAGGR

4

In most situations it does make sense. Imagine an order_details table with a SUM(PRICE) field. If you place it on a related Order form it will automatically get the total for you. Same for max to for example figure out the most expensive line item, etc.

5

Hello Jan

Could it be that generally spoken that from the m-side to a 1-side relationship the implemented behaviour makes sense but not from the 1-sid to the m-side, but I am not sure about that.

Best regards, Robert

jaleman:
In most situations it does make sense. Imagine an order_details table with a SUM(PRICE) field. If you place it on a related Order form it will automatically get the total for you. Same for max to for example figure out the most expensive line item, etc.

6

I’d say the other way around, in general you want summary functions to go from 1 to N. From N to 1 it doesnt make any sense to performm any summary function as there is only 1.