This is one of the reasons why we - in ALLL our database types - disallow NULL values. All fields should have (default) values

can't avoid the nulls produced by the outer joins though,i.e a left one

If I insert an empty string into a varchar field in Oracle, it helpfully inserts a NULL instead

I am not familiar with Oracle;how does it behave when when you put a not null constraint on the column?

catering for nulls is such an important issue that for example C# introduced Nullable Types into the core language