PostgreSQL

When inserting a row into a table, if there is a varchar column and if
in that column the value to be inserted is a zero length string (like
''), then instead of writing a null value, PostgreSQL writes that zero
length string. We are able to do this with delphi which generates such
sql insert phrases. We contacted Borland, but there was no answer. I
don't know if this is a bug, but I'm sure that inserting a null value
instead of a zero length string would help us a lot.