|
Problem IT07789
|
Status: Closed |
IWA: SELECT CAN MISS RESULT ROWS FROM DATA MARTS WITH A N:M CARDINALITY REFERENCE |
| product: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problem description: |
The problem is with a snowflake schema, where a reference on the
second level (or beyond) is not a 1:n cardinality reference.
Consider the following join examples:
a) fact table ---- 1:n reference ----> dimension 1 table
---- n:m reference ----> dimension 2 table :
A query on such a data mart can miss result rows, because
not all the non-unique rows from the
dimension 2 table are gathered for the join with the
dimension 1 table.
b) fact table ---- n:m reference ----> dimension table :
A query on such a data mart produces correct results.
c) fact table ---- n:m reference ----> dimension 1 table
---- n:m reference ----> dimension 2 table :
A query on such a data mart produces correct results.
Here, the reference from fact table to dimension 1 table
simply was made an n:m reference as well
(even though dimension 1 table has unique keys and would
satisfy the requirements for a 1:n reference). |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Users having data marts with n:m cardinality references. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Update to IBM Informix Server 12.10.xC6 *
**************************************************************** |
| Local Fix: |
|
| Solution |
Problem Fixed In IBM Informix Server 12.10.xC6 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 18.03.2015
30.12.2015
30.12.2015 |
| Problem solved at the following versions (IBM BugInfos) |
12.10.xC6
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 12.10.xC5.W1
|
 |
| 12.10.xC6
|
|
