"Arnar Birgisson" <[EMAIL PROTECTED]> writes:
> Hi all,
>
> Say I have this simple model:
>
> DayTimesheet
> date: a Date
> entries: a list of TimeEntry
>
> TimeEntry:
> day: a DayTimesheet
> in: a time (HH:MM)
> out: a time (HH:MM)
>
> DayTimesheet is the parent of TimeEntry in a one-to-many relationship.
>
> What would be the best way of ensuring the following:
>
> 1. Creating DayTimesheet on demand, i.e.
> DayTimesheet.get_by(date=nonexistentdate) would create a new instance
> if needed (inserted on the next flush())
You can try a "get_by" by that specific date and if there's an exception
create the record on the except clause.
> 2. Automatically removing childless DayTimesheet instances - that is,
> when the last TimeEntry is deleted from a DayTimesheet, delete the
> DayTimesheet too?
I had a similar problem... I solved it by scheduling a query like:
DELETE FROM parent_table WHERE id NOT IN (SELECT parent_id FROM child_table
GROUP BY parent_id);
It runs periodically and cleans the database from stale records.
--
Jorge Godoy <[EMAIL PROTECTED]>
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