Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!hplabs!hpda!hpcuhb!hpsmtc1!donovan
From: donovan@hpsmtc1.HP.COM (Donovan Hsieh)
Newsgroups: comp.databases
Subject: Re: One to Many to One to One relationships in Informix SQL  (LONG!!)
Message-ID: <11410004@hpsmtc1.HP.COM>
Date: 15 Dec 88 21:49:40 GMT
References: <9176@ihlpb.ATT.COM>
Organization: Hewlett Packard, Cupertino
Lines: 28

According to your base note which states "Leadsource, location, and type make
up a unique field". Your sample table A in response 2 has just invalidated
this assumption  :

TABLE A
Leadssource        Location        Type      leadnumber                        
-----------        --------        ----      ----------

  YRHD                B1            R           1347    (1)
  YRHD                B1            R           1653    (2)
  YRHD                B1            B            987    (3)
  CBW                 A0            R            466    (4)
  CBW                 A0            S           1433    (5)
  CBW                 A0            S           1944    (6)
  USER                A0            S            616    (7)
  USER                A0            S            789    (8)
  USER                A0            S            987    (9)
  (etc)


The tuples (1) & (2) show that "Leadsource Location Type" does not uniquely
identify the "leadnumber". This invalidates my initial assumption of FD 1 listed
in response 1 and your statement as described above. Further more, tuples (4)
to (9) also invalidate the FD 2 since "Location" does not uniquely identify
the "Leadsource".

At this point, I would suggest you to either use a Entity-Relationship diagram
or formal Funtional Dependency to specify your attribute relationship
before I could make meaningful recommendation.