أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
VARCHAR is reserved by Oracle to support distinction between NULL and empty string in future, as ANSI standard prescribes. VARCHAR2 does not distinguish between a NULL and empty string, and never will. If you rely on empty string and NULL being the same thing, you should use VARCHAR2.