One of my clients will be using a DB2 server for my application's
database. I have several single-column foreign keys where I need to have
null values for some records, and this works fine in SQL Server,
InterBase and Access, but my client says that DB2 does not accept nulls
in foreign keys.

This seems totally weird to me, so I was wondering if anyone can confirm
or deny? If DB2 does allow nulls in foreign keys, what might the cause
for my client's problems be?

Kjell

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For clarity - the SQL is as follows:

CREATE TABLE FieldList (
  FieldId char (3) NOT NULL PRIMARY KEY ,
  FieldName varchar (20)
)

CREATE TABLE FieldPlaces (
  PlaceNumber int NOT NULL PRIMARY KEY ,
  FieldId char (3) REFERENCES FieldList (FieldId)
)

INSERT INTO FieldList VALUES ('XXX','TheName')
INSERT INTO FieldList VALUES ('YYY','SomeOtherName')
INSERT INTO FieldList VALUES ('ZZZ',null)
INSERT INTO FieldPlaces VALUES (1,'ZZZ')
INSERT INTO FieldPlaces VALUES (2,'XXX')

So far everything's fine, but according to my client, the following will
fail:

INSERT INTO FieldPlaces VALUES (3,null)

My client is currently on vacation, and I'm afraid he hasn't informed me
the exact error message. Any clues?