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? ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to majordomo@xxxxxxxxxxxxxx)