Hello:


For obtain a value indicating if a column allow null values the GDS
implementation make this in isc_dsql_fetch:

xsqlda.sqlvar[i].sqlind = (row[i] == null ? -1 : 0);


This is not a correct way for doing this, only if you have luck you
will
obtain the correct value.



Best regards
Carlos Guzmán Álvarez
Vigo-Spain


P.D.: if it can help, I have this solved in the .net data provider.