Denormalizing Source Data Tables
If data is highly normalized, it may not map clearly to OLAP models. Normalized data is grouped and has no redundant data. You can use normalized source tables to create an OLAP model by specifying joins, but it may be more efficient to create a new table of denormalized data in the RDBMS.
If you use the denormalized data source, Integration Server does not need to compute the joins when building OLAP models.
In this example, in the first three tables, data is highly normalized, minimizing redundant data:
Table 8. Normalized Product Family Data
FAMILYID | FAMILYDESC |
|---|
100 | Colas |
200 | Root Beer |
Table 9. Normalized Product Data
PRODID | FAMILYID |
|---|
100-10 | 100 |
100-20 | 100 |
100-30 | 100 |
Table 10. Normalized Product Description Data
PRODID | PRODDESC |
|---|
100-10 | Cola |
100-20 | Diet Cola |
100-30 | Caffeine Free Cola |
The following shows denormalized data in one table:
Table 11. Denormalized Product Data
FAMILYID | FAMILYDESC | PRODID | PRODDESC |
|---|
100 | Colas | 100-10 | Cola |
100 | Colas | 100-20 | Diet Cola |
100 | Colas | 100-30 | Caffeine Free Cola |
100 | Colas | 100-10 | Cola |
200 | Root Beer | 200-10 | Root Beer |