Occasionally questions will come up about the STAR schema and how it maps to fields in P6. The STAR schema is comprised of data pulled from the P6 EPPM Extended view schema, the rest of the data is calculated as part of the Transformation process. Calculated data includes - historical captures, hierarchies, burndown and work planning calculations, and many others.
If you would like to see how the Extended schema fields are mapped a good place to start is by looking in the ETL_MAPPING table. Choose what your source schema version is (example: EPPM 8.3 = 83)
select * from etl_mapping where source_version = 83;
From here you can view how these fields are directly mapped to the staging tables (example: W_PROJECT_DS). These fields would map similarly to the corresponding dimension or fact tables. This information is also available in the P6 Reporting Database installation directory \res folder in the file mapping.tcsv.