Multiple Fact Reporting on (Non-)Conforming dimensions – Part II

Last week I have been blogging about Multiple Fact Reporting on (Non-)Conforming dimensions. Thanks to Nicolae I was triggered to do some further investigation on this topic. He had a question; What happens when you want to filter on a non-conforming dimension?

When you filter an a non-conforming dimension, you could get a null value for the fact which has all the dimensions as conforming.

 
 

Is this not exactly how the Oracle BI-server works? We have created one logical fact table and two different logical table sources (LTS). The Oracle BI-server creates seperate queries for each LTS in a Oracle BI Answers query.

Query I:

Query I connects fact table 1 to all the dimensions, including a filter on the non-conforming dimension.

Query II:

Query II connects fact table 2 one to the conforming dimensions only. Because there is no physical relationship between fact table 2 and the non-conforming dimension, it is not possible to filter query II on  dtnc1.value3 = ‘3CCC3’ as well.

The results of both queries:

Lucky enough for me Nicolas did some investigating himself to:

It looks like the most easy solution is to filter on the fact table which has all the dimensions as conforming. In this case, that would be; Fct1 Value1.

I will try to ask some other sources what their solution is to this ‘problem’.

More to come.

Multiple Fact Reporting on (Non-)Conforming dimensions

There are some questions, which are popping up at the Oracle BI EE Forums regularly. One of those questions is; 

*** How to model multiple facts against (non-) conforming dimensions?

I will try to work things out. Click on the images to see more detail.

Note: I am aware of the extra white space between the images. That’s not intended functionality, but lack of knowledge of  WordPress. 

Picture the following:

There are two fact tables and three dimension tables. FACT_TABLE_1 has two conformed dimension tables; DIM_TABLE_CONF_1 and DIM_TABLE_CONF_2 and one non-conformed dimension table DIM_TABLE_NON_CONF_1.

FACT_TABLE_2 has two conformed dimension tables; DIM_TABLE_CONF_1 and DIM_TABLE_CONF_2. 

The Physical Model would have the following structure:

Physical Diagram

Based on the Physical Model we could construct the following Logical Model: 

Logical Diagram

I have created one fact table which contains Logical Table Sources (LTS) for FACT_TABLE_1 and FACT_TABLE_2

Logical Model

As you can see I have created Dimensions (Hierarchy’s) for each Dimension Table.   

FACT_TABLE_2 has no physical relationship with DIM_TABLE_NON_CONF_1. Therefore you should set the logical levels for FACT_TABLE_2 to the ‘Grand Total’-level of DIM_TABLE_NON_CONF_1. This way the Oracle BI Server won’t look for a join between DIM_TABLE_NON_CONF_1 and FACT_TABLE_2.

If you want to avoid nulls, set the detail levels for the facts. Set the ‘Grand Total’-levels for the metrics as well.

Logical Table Source - Fact I
Logical Table Source - Fact II
Logical Column - Fact II

If we take a look at Oracle BI Answers, we can create a report which contains data from the following tables;

  • DIM_TABLE_CONF_1
  • DIM_TABLE_CONF_2
  • FACT_TABLE_1
  • FACT_TABLE_2 
Oracle BI Answers - Conformed Dimension

Now we can bring data from DIM_TABLE_NON_CONF_1 into this report. It is impossible to devide data from FACT_TABLE_2 over this dimension. Therefore the data will be the same for every value of this dimension.

Oracle BI Answers - (Non-) Conformed Dimension

*** Summary:

 It’s possible to report on facts and dimensions which not have a physical relationship to each other. Just make sure you create dimensions (hierarchy’s) for every dimension table. Next to that you should set the logical levels for your logical tables.