Please start any new threads on our new
site at https://forums.sqlteam.com. We've got lots of great SQL Server
experts to answer whatever question you can come up with.
| Author |
Topic |
|
carumuga
Posting Yak Master
174 Posts |
 Posted - 2009-01-23 : 09:32:52
|
| Hi,Could anyone explain Inferred members in SCD scenario.Thanks in advance. |
|
|
visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2009-01-23 : 11:30:46
|
| inferred members occur in cases where you've two dimensions (say dim1 & dim2) where one is dependent on another. suppose if dim2 is dependent on dim1 with dim1key as fk in it. while populating dim2, you need to lookup dim1 with value of dim1's business key to get fk value which is its surrogate key.so dim1 should have all business key values which are reffered in dim2. so ideally we process dim1 before dim2. However, in some cases due to failure in dim1, the reqd values wont get populated in dim1. in such cases, when we lookup values of dim2 in dim1 for surrogate key, they wont find it. in such cases, as we know it should be a valid value existing in dim1, we populate the fk from dim2 into dim1 and use generated surrogate key values (id column) as required value in dim2. we use a bit field in dim called inferred to indicate that these values are populated from another dim with only fk value and rest all fields having default value (like 'unknown') and the original values need to be updated during next population of dim1.its called inferred |
 |
|
|
visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
|
|
|
|
|
SCD - Inferred members