This looks like the one I need, I want all projects whose date range
has any kind of overlap with the given date range.
Thanks, will try it!
On Thu, Nov 17, 2016 at 4:10 PM, Alexander Burger <a...@software-lab.de> wrote:
> Hi Henrik,
>> (class +Proj +Macropisobj)
>> (rel id (+Key +Number))
>> (rel nm (+Ref +String))
>> (rel sDate (+Ref +String))
>> (rel eDate (+Ref +String))
>> (dm getCurrent> (Sdate Edate)
>> (filter '((P) (or
>> (< Sdate (; P sDate) Edate)
>> (< Sdate (; P eDate) Edate)
>> (< Sdate (; P sDate) (; P eDate) Edate) ) )
>> (collect 'id This) ) )
>> But how would the above problem be solved with Pilog and select if we have
>> more than "a couple of hundred objects" in the database?
> If you know that the *result* will be within a few hundred hits (not the
> total DB size), and the difference between start and end is less than
> e.g. 100 days, then you could first restrict the collection a bit
> (collect 'sDate '+Proj Sdate (+ Edate 100))
> (works of course only for +Date types), and then filter that further.
> This is surely the most efficient way for a small set of results.
> The same you can do in Pilog with the 'db' predicate for an larger
> result set, and if you want to avoid a 'select'
> (? @Rng (cons Sdate (+ Edate 100))
> (db sDate +Proj @Rng @Proj) )
> But 'select' is the most general - and on big data sets perhaps the most
> efficient - way. You could try
> @Sdate (cons Sdate T) # Range with open end
> @Edate (cons Edate NIL) # Reversed range with open start
> (select (@Proj)
> ((sDate +Proj @Sdate) (eDate +Proj @Edate)) # Search two indexes in
> (range @Sdate @Proj sDate) # Check ranges
> (range @Edate @Proj eDate) ) ) # Check ranges
> I haven't tested this ;)
> ♪♫ Alex
> UNSUBSCRIBE: mailto:firstname.lastname@example.org?subject=Unsubscribe