On 2/1/07, Murray Cumming <[EMAIL PROTECTED]> wrote: > On Wed, 2007-01-31 at 22:45 +0100, Johannes Schmid wrote: > > Hi Vivien! > > > > Well, the docs are quite confusing in this point because they just > > mention that the parameter cannot be "0" if set_not_null(TRUE) was > > called. Anyway an empty string is usually non-NULL (especially in a C++ > > context). > > There is no concept of a NULL std::string in C++. Either string.empty() > is true or it's not - there's nothing in between. > > > Maybe the docs and the method name could be improved. > > For strings, NULLness is not very interesting. It's a concept from SQL > that isn't useful in an API. > > Or do you have an example of a situation in which it is useful for the > application to distinguish between empty-string and NULL for a text > field? How would the application (or libgnomedb) show this distinction?
In Libgda, a NULL value is either represented using the NULL pointer, or a GValue where all the attributes are 0. A Libgnomedb data entry or data cell renderer will simply display an empty string (so no difference with an empty string there); and if the actions are shown, then the user will notice that the value is actually NULL. Vivien _______________________________________________ gnome-db-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/gnome-db-list
