Sorry. It works (I got something wrong earlier) but the limit has gone away. I just have to ensure that there is ay least one record.
On Wed, Jan 22, 2014 at 5:28 PM, Jayadevan M <maymala.jayade...@gmail.com>wrote: > I tried that. I get the error - > <type 'exceptions.AttributeError'> 'Row' object has no attribute 'select' > By the way, the "=" works. Additional information, this function is under > modules. Do I have to imprt something to make the select construct work? > > > On Wed, Jan 22, 2014 at 5:22 PM, Johann Spies <johann.sp...@gmail.com>wrote: > >> Oops. That should be >> cond = db(db.mytable.id==someid).select(db.mytable.id) >> >> >> On 22 January 2014 13:50, Johann Spies <johann.sp...@gmail.com> wrote: >> >>> cond = db.mytable(id=someid).select(db.mytable.id) >>> >>> Regards >>> Johann >>> >>> >>> On 22 January 2014 10:50, Jayadevan M <maymala.jayade...@gmail.com>wrote: >>> >>>> I am checking for existence of record in a table >>>> >>>> cond = db.mytable(id=someid) >>>> if not cond : >>>> do something >>>> >>>> This works fine. The query executed selects *all* columns and adds >>>> LIMIT 1 OFFSET 0; The LIMIT and OFFSET are OK. Since I want to just check >>>> for existence of a record, how can I rewrite this so that we have only the >>>> id column selected? I am trying to avoid a table scan and have just an >>>> index scan. >>>> >>>> -- >>>> 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 web2py+unsubscr...@googlegroups.com. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>> >>> >>> >>> -- >>> Because experiencing your loyal love is better than life itself, >>> my lips will praise you. (Psalm 63:3) >>> >> >> >> >> -- >> Because experiencing your loyal love is better than life itself, >> my lips will praise you. (Psalm 63:3) >> >> -- >> 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 a topic in the >> Google Groups "web2py-users" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/web2py/XYeLmZjQ6fY/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> web2py+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- 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 web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
