Hi,
My case:
I have a complex query which returns a huge amount of data. It returns
data from
two tables which are joined.
Because the amount of data is huge I cannot load all of it into memory.
For this reason I want to use an iterated query.
I also want to prevent cayenne from executing a query for each detail record
so I want to use prefetching.
What I tried:
- I'm using cayenne 2.0.4.
- I use SQLTemplate to instantiate the query.
- I set the page size to 1000 to prevent loading the whole db
(required for postgres)
- I use performIteratedQuery to run the query.
- As I get DataRows back from the iterated query I use
dataContext.objectFromDataRow(..) to create my objects
The Problem:
The relation is not automatically setup. This means that for every
record I access the detail table a query is executed.
My Questions:
- How should I use prefetching in combination with SQLTemplate and
an iterated query which returns DataRows?
- Is there a way to manually setup this relationship (without
changing the state of the parent object?)
- Is there another way to do what I want using Cayenne?
