When creating a Cube in OWB10g R2 one has the possibility to define aggregations to be performed for the Dimensions that the cube references.
When defining the aggregations you are able to select the aggregation method (sum, max, min, first, last, average, hierarchical average etc.) and the data refresh method (On demand or On commit).
You are also able to select the dimension levels for which data should be pre computed. If you do not select levels for the dimensions, OWB will perform aggregations for alternative levels starting from the lowest level. According to the documentation, for ROLAP cubes Warehouse Builder implements these aggregations by creating materialized views. The documentation also states that these materialized views are NOT displayed under the Materialized Views node in the Project Explorer of OWB Design Center.
I had created a few Cubes using the aggregation setup but I couldnâ€™t find any materialized views in the database. I noticed that in the Cubes Configuration screen there is the possibility to name the tablespace that is to be used for the materialized views.
So I created a tablespace â€œMVIEWTâ€, added the tablespace name to the Cubes configuration, created a new mapping for the Cube, deployed and executed the mapping but unfortunately the tablespace remained empty. So I decide to contact Oracle Support to check with them where the materialized views are being placed. They were able to confirm that this functionality does not work yet and hopefully it will be activated in the next release.
2 thoughts on “When creating Cubes in OWB10g R2, are materialized views automatically created as well?”
I recently had a problem with deploying a dimension and to my surprize I found that OWB uses “Deploy Data Objects Only” for the Deployment Option while in the Paris version “Deploy All” was the default value, which is the correct value according to the documentation. If you set it to “Deploy All” the CWM2 scripts are created and displayed. If you do not use the “Deploy All” option, the olapsys tables are not be filled.
Very interesting. I looked and couldn’t find them before, but thought it was something I was doing wrong.
Also – have you been able to view the CWM2 scripts that OWB is also supposed to create? I assume they are being created and run, because the dimensions and cubes are visible using D40 and the dimension viewer, but I’ve never been able to view the scripts within the Control Center manager.
Comments are closed.