I used this compact way and i noticed it only returns one record. for example
table db.badass id name value 1 trump 10 2 trump 20 3 hilary 30 db.badass(name="trump") only returns record with id =1 Regards António 2016-11-21 15:47 GMT+00:00 Massimo Di Pierro <[email protected]>: > It depends > > a query is always field==value so you can do > > query = db.table.field == value > row = db(query).select(limitby=(0,10)).first() > > or > > row = db.table(query) > > (they are equivalent) > > But db.table(...) can take an "implicit query" > > db.table(fieldname=value) > > which is a more compact way to do > > db.table(db.table.field==value) > > The most common way to use db.table(...) is this > > db.table(id) > > or > > db.table(id, fieldname=value) # returns the record only of the > fieldname==value > > or > > db.table(id, query) # returns the record only if the query is true. > > > > On Sunday, 20 November 2016 09:08:38 UTC-6, Meinolf wrote: >> >> Hi Massimo >> >> Just came across this post and got a bit alarmed, so when i check if a >> record exists i don't have to use the usual '==' but instead '=' ? >> >> On Monday, October 10, 2011 at 3:55:27 PM UTC+2, Massimo Di Pierro wrote: >>> >>> row = db.postcode_cache(postcode=postcode) >>> if not row: >>> db.postcode_cache.insert(postcode=postcode,nearset=nearest) >>> elif not row.nearest: row.update_record(nearset=nearest) >>> else: pass # do nothing >>> >>> On Oct 10, 8:22 am, Chris Rowson <[email protected]> wrote: >>> > Hi list, >>> > >>> > I have a database table which looks like this: >>> > >>> > postcode_cache >>> > ------------------------ >>> > postcode (UNIQUE) >>> > lat >>> > lon >>> > nearest >>> > >>> > I want to test first whether or not a record exists for 'postcode' and >>> > if a record does exist, I want to check whether the 'nearest' field >>> > contains any data. >>> > >>> > I've tried this: >>> > >>> > if db(db.postcode_cache.postcode==postcode).select().first()==None: >>> > create_a_new_postcode_record() >>> > >>> > elif >>> > db(db.postcode_cache.postcode==postcode).select(db.postcode_cache.nearest)= >>> =None: >>> > populate_the_nearest_field() >>> > >>> > else: >>> > nothing_to_do() >>> > >>> > And while the check to establish whether or not a record exists seems >>> > to work, the check to see whether or not the 'nearest' field within >>> > the record is populated doesn't seem to work. >>> > >>> > Can anyone tell me what I'm doing wrong please? >>> > >>> > Thank you, >>> > >>> > Chris >> >> -- > Resources: > - http://web2py.com > - http://web2py.com/book (Documentation) > - http://github.com/web2py/web2py (Source code) > - https://code.google.com/p/web2py/issues/list (Report Issues) > --- > You received this message because you are subscribed to the Google Groups > "web2py-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
