Yes, there is a point for checking that a nil pointer is not passed to the constructor of std::string. The change will be checked in shortly.
John On 1/24/12 1:35 PM, Dominique Prunier wrote: > Hey, > > About nulls, i do agree with you. I'm not shocked to say "NULL <=> <empty > string>", as far as i know, it is what Oracle does. > The attached patch should fix my issue for categories. Later on, we could > check a few things about bundles (more specifically, colValue::write) to make > them more consistent. > > Thanks, > > -----Original Message----- > From: K. John Wu [mailto:[email protected]] > Sent: Tuesday, January 24, 2012 4:30 PM > To: Dominique Prunier > Cc: FastBit Users > Subject: Re: [FastBit-users] ibis::relic::keys performance and CATEGORY > columns > > Hi, Dominique, > > The intention was to not have NULL values in the results. The query > answering function take into account of the null masks to eliminate > NULL values. Internally, strings are represented as std::string. The > constructor can not usually take a nil pointer. The particular error > might due to this problem with passing a nil to std::string > constructor. Anyway, there might be an issue if we have a NULL in the > answer set. It could be worthwhile to look into this further. > > The problem with NULL string values is that all three forms you've > suggested could be valid string values. Presumably, we could settle > on one, say the empty string "". This might be the most reasonable > choice as the CSV reader actually will treat empty strings as NULL > values. This probably means that other database systems output empty > strings for NULL values. > > John > > On 1/24/12 12:40 PM, Dominique Prunier wrote: >> Hmm, just discovered something bad with the patch. If the key is 0 >> (which means NULL), the new ibis::category::selectStrings fails >> with "basic_string::_S_construct NULL not valid". The is no clear >> convention for what is a null string in FastBit interfaces ("", >> NULL, "<NULL>") but i guess an empty string would be the best fit >> here, right ? >> >> Thanks, >> >> _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
