Werner wrote: > Bruce wrote: > >> This has sort of been asked before. However, the answers I have found >> haven't >> helped. >> >> My database has a LOT of integer fields, arranged into sets of fieldwork >> results. The majority of them contain nulls, quite validly as the data for >> a >> particular set may not have been entered or even collected yet. >> >> My Gambas problem is creating the classes for the various plot types. >> Within >> Gambas the data items are integers. When I try and read the existing datum >> point into the class (as in dp.rangeheight=$dbresult!rangeheight ) it is >> complaining that the value is a null not an integer, as in "wanted integer, >> got null instead"). >> >> Now, coercing the value of the object data to zero is NOT valid, as in the >> above example, the rangeheight is null not zero, as zero means 0m above the >> basepoint. Similarly, coercing it to a negative value wont work either, as >> that means meters below the base point. >> >> Is there any way to set the value of an integer variable to an >> "uninitalised" >> state? >> >> bruce >> >> > A solution might be to use the Variant data type instead of Integer. > Alternatively, you could define a class that holds a data point plus a > flag whether the data is valid. > > Werner > ...or you could set empty data points to -0 which is most significant bit set to 1 all other bits 0
...or you might be able to use TRY whenever accessing a data point to catch the exception. In any case there needs to be a test whether the data is valid. As you said, the majority of data fields is empty. If you have a humongous amount of data it might be worth looking into "spare matrix" compression (what spreadsheets do) Werner ------------------------------------------------------------------------------ This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
