You should not have to implement either. The implementation of has_data runs a not_null query over the aggregation period. In turn not_null either consults the database or, if it's an xtype, runs get_scalar() over the aggregation period. The first non-null value seen causes it to return True.
Of course, that's a fairly compute intensive way of checking for non-null xtype values, but it will work for any xtype. One could optimize the calculation with a specialized version for your type, but so far I haven't heard of a case where it's needed. -tk On Fri, Feb 23, 2024 at 7:48 AM Karen K <kk4468...@gmail.com> wrote: > Do I have to implement both the not_null and has_data aggregation in an > XType extension? > > > Tom Keffer schrieb am Freitag, 23. Februar 2024 um 14:01:45 UTC+1: > > The aggregation not_null does not check first to see if the type exists. > If you know the type exists, it's slightly faster. > > In practice, I don't think it's very useful. I may remove it from the > documentation. > > On Fri, Feb 23, 2024 at 3:48 AM Karen K <kk44...@gmail.com> wrote: > > What is the difference between the aggregation types has_data and not_null > according to the documentation in > http://weewx.com/docs/5.0/reference/aggtypes/. > > -- > You received this message because you are subscribed to the Google Groups > "weewx-user" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to weewx-user+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/weewx-user/8abfecfb-7fe5-4e6c-aace-540ed933ea8en%40googlegroups.com > <https://groups.google.com/d/msgid/weewx-user/8abfecfb-7fe5-4e6c-aace-540ed933ea8en%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/CAPq0zEAGi1sLuP_23WvoXMc3F1eusA1LK45OMVCtgxCRq39rPQ%40mail.gmail.com.
