If I define a primary key:
name TEXT NOT NULL,
address INET,
PRIMARY KEY(name, address)
the definition (seen by \d) becomes:
name | text | not null
address | inet | not null
"address" is now not null, which I do not want. It seems unnecessary:
I just want the tuple (name, address) to be unique, which seems
possible even if some 'address' values are NULL.
It does not appear to be documented in
http://www.postgresql.org/docs/7.4/interactive/ddl-constraints.html#AEN1975.
Is there a workaround?